I n t e r n e t – -> ´´The Internet (portmanteau of interconnected network) is the global system of interconnected computer networks that uses the Internet protocol suite (TCP/IP) to link devices worldwide. It is a network of networks that consists of private, public, academic, business, and government networks of local to global scope, linked by a broad array of electronic, wireless, and optical networking technologies.´´ @ ´´The world-wide market for gene-altered mice is predicted to grow to $1.59 billion by 2022, growing at a rate of 7.5 percent per year.[59] The theoretical basis for the stored-program computer was laid by Alan Turing in his 1936 paper.´´ https://en.wikipedia.org/wiki/Computer @ https://en.wikipedia.org/wiki/Internet @ ´´The laboratory mouse is a small mammal of the order Rodentia which is bred and used for scientific research. Laboratory mice are usually of the species Mus musculus. They are the most commonly used mammalian research model and are used for research in genetics, psychology, medicine and other scientific disciplines.´´ https://en.wikipedia.org/wiki/Laboratory_mouse & OTHER VERY IMPORTANT INFORMATION

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The Quantum Information Edge Launches to Accelerate Quantum Computing R&D for Breakthrough Science

News Release Laurel Kellner 510-486-5375 • December 20, 2019Share247TweetRedditShare247SHARES

A nationwide alliance of national labs, universities, and industry launched today to advance the frontiers of quantum computing systems designed to solve urgent scientific challenges and maintain U.S. leadership in next-generation information technology.

The Quantum Information Edge strategic alliance is led by two of the U.S. Department of Energy’s national laboratories: Lawrence Berkeley National Laboratory (Berkeley Lab) and Sandia National Laboratories. The alliance also includes experts from the University of Maryland, Duke University, Harvard University, University of Colorado Boulder, UC Berkeley, Caltech, MIT Lincoln Laboratory, Massachusetts Institute of Technology, and the University of New Mexico.

(Credit: sakkmesterke/Shutterstock)

This partnership brings together an unprecedented breadth of world-leading expertise and capabilities in computer science, materials science, physics, mathematics, and engineering to pioneer practical advances in quantum systems.

The alliance will identify the most impactful scientific applications that stand to benefit from quantum computing and engineer the hardware and software systems to run these applications. Using advanced hardware including superconducting circuits and naturally occurring atomic systems, the alliance will explore ways to achieve practical quantum advantage – meaning the systems can outperform state-of-the-art classical methods for important scientific and engineering problems.

The team will also help grow the workforce needed to keep the nation at the forefront of quantum information science for years to come, share its advances with the broader scientific community to drive the innovation ecosystem, and work with industry to translate promising technologies into real-world applications.

“We are at the threshold of significant advances in quantum information science. To break new ground, The Quantum Information Edge will accelerate quantum R&D by simultaneously pursuing solutions across a broad range of science and technology areas, and integrating these efforts to build working quantum computing systems that benefit the nation and science,” said Irfan Siddiqi, director of Berkeley Lab’s Advanced Quantum Testbed and a faculty scientist in the Lab’s Computational Research and Materials Sciences divisions.

“Through collaboration and innovation focused on tangible technology demonstrations, The Quantum Information Edge will amplify the return-on-investment of quantum research within the U.S. by accelerating progress toward achieving practical quantum computing systems,” said Scott Collis, director of Computing Research at Sandia.

The alliance’s work on programmable quantum systems has the potential to solve scientific problems that are far beyond the reach of today’s machines, in areas such as information processing, simulations, and metrology. It could transform the design of solar cells, new materials, pharmaceuticals, agricultural fertilizers, and probe the mysteries of physics and the universe, among many applications.

To make this a reality, the alliance will advance quantum information systems using several hardware approaches, including superconducting, trapped ion, and trapped atom quantum bits (or qubits). The alliance will explore how to suppress noise and errors in multi-qubit quantum processors, which severely degrade system performance, develop new computing algorithms to control qubits, and engineer new techniques to fabricate, control, and interconnect qubits. Theoretical computer scientists, physicists, engineers, and chemists will help understand how best to apply these systems to important scientific problems.

“The quantum processors developed by The Quantum Information Edge will explore the mysterious properties of complex quantum systems in ways never before possible, opening unprecedented opportunities for scientific discovery while also posing new challenges. Our world-class theory team, working closely with the hardware builders, will exploit this powerful technology to advance the frontiers of the physical and computational sciences,” said John Preskill, the Richard P. Feynman Professor of Theoretical Physics at the California Institute of Technology.

“We will continually build and use full quantum systems, not just the components, to forge new scientific opportunities in information processing that are not possible in conventional research programs,” said Christopher Monroe, Distinguished Professor of Physics at the University of Maryland.

“By developing and applying programmable quantum information systems, we hope to define a new frontier at the cutting edge of science and engineering. These efforts have a great potential for scientific discoveries and for identifying the first useful applications of quantum machines,” said Mikhail Lukin, the George Vasmer Leverett Professor of Physics at Harvard and a co-Director of Harvard Quantum Initiative.

“The broad scope of quantum information science and technology demands responses from a diverse set of research groups who will coordinate their scientific visions and technologies to identify and solve practical problems, bring unforeseen benefits, and uncover scientific secrets,” said Jun Ye, a professor at the University of Colorado Boulder and a fellow of the National Institute of Standards and Technology.


Founded in 1931 on the belief that the biggest scientific challenges are best addressed by teams, Lawrence Berkeley National Laboratory and its scientists have been recognized with 13 Nobel Prizes. Today, Berkeley Lab researchers develop sustainable energy and environmental solutions, create useful new materials, advance the frontiers of computing, and probe the mysteries of life, matter, and the universe. Scientists from around the world rely on the Lab’s facilities for their own discovery science.

Berkeley Lab is a multiprogram national laboratory, managed by the University of California for the U.S. Department of Energy’s Office of Science. DOE’s Office of Science is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, please visit energy.gov/science.Share247TweetRedditShare247SHARESTAGS: computingquantum


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From Wikipedia, the free encyclopediaJump to navigationJump to searchThis article is about the worldwide computer network. For other uses, see Internet (disambiguation).Not to be confused with the World Wide Web.

An Opte Project visualization of routing paths through a portion of the Internet
Information infrastructure[show]
 Internet portal
Computer network types
by spatial scope
NanoscaleNear-field (NFC)Body (BAN)Personal (PAN)Near-me (NAN)Local (LAN)Home (HAN)Storage (SAN)Wireless (WLAN)Campus (CAN)BackboneMetropolitan (MAN)Municipal wireless (MWN)Wide (WAN)Cloud (IAN)InternetInterplanetary Internet

Internet users per 100 population members and GDP per capita for selected countries.

The Internet (portmanteau of interconnected network) is the global system of interconnected computer networks that uses the Internet protocol suite (TCP/IP) to link devices worldwide. It is a network of networks that consists of private, public, academic, business, and government networks of local to global scope, linked by a broad array of electronic, wireless, and optical networking technologies. The Internet carries a vast range of information resources and services, such as the inter-linked hypertext documents and applications of the World Wide Web (WWW), electronic mailtelephony, and file sharing.

The origins of the Internet date back to research commissioned by the United States Department of Defense in the 1960s to build robust, fault-tolerant communication with computer networks.[1] The primary precursor network, the ARPANET, initially served as a backbone for interconnection of regional academic and military networks in the 1980s. The funding of the National Science Foundation Network as a new backbone in the 1980s, as well as private funding for other commercial extensions, led to worldwide participation in the development of new networking technologies, and the merger of many networks.[2] The linking of commercial networks and enterprises by the early 1990s marked the beginning of the transition to the modern Internet,[3] and generated a sustained exponential growth as generations of institutional, personal, and mobile computers were connected to the network. Although the Internet was widely used by academia in the 1980s, commercialization incorporated its services and technologies into virtually every aspect of modern life.

Most traditional communication media, including telephony, radio, television, paper mail and newspapers are reshaped, redefined, or even bypassed by the Internet, giving birth to new services such as emailInternet telephonyInternet televisiononline music, digital newspapers, and video streaming websites. Newspaper, book, and other print publishing are adapting to website technology, or are reshaped into bloggingweb feeds and online news aggregators. The Internet has enabled and accelerated new forms of personal interactions through instant messagingInternet forums, and social networkingOnline shopping has grown exponentially both for major retailers and small businesses and entrepreneurs, as it enables firms to extend their “brick and mortar” presence to serve a larger market or even sell goods and services entirely onlineBusiness-to-business and financial services on the Internet affect supply chains across entire industries.

The Internet has no single centralized governance in either technological implementation or policies for access and usage; each constituent network sets its own policies.[4] The overreaching definitions of the two principal name spaces in the Internet, the Internet Protocol address (IP address) space and the Domain Name System (DNS), are directed by a maintainer organization, the Internet Corporation for Assigned Names and Numbers (ICANN). The technical underpinning and standardization of the core protocols is an activity of the Internet Engineering Task Force (IETF), a non-profit organization of loosely affiliated international participants that anyone may associate with by contributing technical expertise.[5] In November 2006, the Internet was included on USA Todays list of New Seven Wonders.[6]



The Internet Messenger by Buky Schwartz, located in HolonIsraelSee also: Capitalization of “Internet”

When the term Internet is used to refer to the specific global system of interconnected Internet Protocol (IP) networks, the word is a proper noun according to the Chicago Manual of Style[7] that should be written with an initial capital letter. In common use and the media, it is often not capitalized, viz. the internet. Some guides specify that the word should be capitalized when used as a noun, but not capitalized when used as an adjective.[8] The Internet is also often referred to as the Net, as a short form of network. Historically, as early as 1849, the word internetted was used uncapitalized as an adjective, meaning interconnected or interwoven.[9] The designers of early computer networks used internet both as a noun and as a verb in shorthand form of internetwork or internetworking, meaning interconnecting computer networks.[10][11]

The terms Internet and World Wide Web are often used interchangeably in everyday speech; it is common to speak of “going on the Internet” when using a web browser to view web pages. However, the World Wide Web or the Web is only one of a large number of Internet services.[12][13] The Web is a collection of interconnected documents (web pages) and other web resources, linked by hyperlinks and URLs.[14] The term Interweb is a portmanteau of Internet and World Wide Web typically used sarcastically to parody a technically unsavvy user.


Main articles: History of the Internet and History of the World Wide Web

Research into packet switching, one of the fundamental Internet technologies, started in the work of Paul Baran in the early 1960s and, independently, Donald Davies in 1965.[15] Packet-switched networks such as the NPL networkARPANET, the Merit Network, and CYCLADES were developed in the late 1960s and early 1970s.[16] ARPANET development began with two network nodes which were interconnected between the Network Measurement Center at the University of California, Los Angeles (UCLA) Henry Samueli School of Engineering and Applied Science directed by Leonard Kleinrock, and the NLS system at SRI International (SRI) by Douglas Engelbart in Menlo Park, California, on 29 October 1969.[17] The third site was the Culler-Fried Interactive Mathematics Center at the University of California, Santa Barbara, followed by the University of Utah Graphics Department. In an early sign of future growth, fifteen sites were connected to the young ARPANET by the end of 1971.[18][19] These early years were documented in the 1972 film Computer Networks: The Heralds of Resource Sharing.

Early international collaborations for the ARPANET were rare. Connections were made in 1973 to the Norwegian Seismic Array (NORSAR) via a satellite station in Tanum, Sweden, and to Peter Kirstein‘s research group at University College London.[20][21][22] The ARPANET project and international working groups led to the development of various protocols and standards by which multiple separate networks could become a single network or “a network of networks”.[23] In 1974, Vint Cerf and Bob Kahn used the term internet as a shorthand for internetworking in RFC 675,[11] and later RFCs repeated this use.[24] Cerf and Khan credit Louis Pouzin with important influences on TCP/IP design. Commercial PTT providers were concerned with developing X.25 public data networks.[25]

Access to the ARPANET was expanded in 1981 when the National Science Foundation (NSF) funded the Computer Science Network (CSNET). In 1982, the Internet Protocol Suite (TCP/IP) was standardized, which permitted worldwide proliferation of interconnected networks. TCP/IP network access expanded again in 1986 when the National Science Foundation Network (NSFNet) provided access to supercomputer sites in the United States for researchers, first at speeds of 56 kbit/s and later at 1.5 Mbit/s and 45 Mbit/s.[26] Commercial Internet service providers (ISPs) emerged in the late 1980s and early 1990s. The ARPANET was decommissioned in 1990.T3 NSFNET Backbone, c. 1992.

The Internet expanded into Europe, South Korea, Japan and Australia in the 1980s.[27][28][29] The beginning of dedicated transatlantic communication between the NSFNET and networks in Europe was established with a low-speed satellite relay between Princeton University and Stockholm, Sweden in December 1988.[30] Although other network protocols such as UUCP had global reach well before this time, this marked the beginning of the Internet as an intercontinental network.

Steady advances in semiconductor technology and optical networking created new economic opportunities for commercial involvement in the expansion of the network in its core and for delivering services to the public. In mid-1989, MCI Mail and Compuserve established connections to the Internet, delivering email and public access products to the half million users of the Internet.[31] Just months later, on 1 January 1990, PSInet launched an alternate Internet backbone for commercial use; one of the networks that added to the core of the commercial Internet of later years. In March 1990, the first high-speed T1 (1.5 Mbit/s) link between the NSFNET and Europe was installed between Cornell University and CERN, allowing much more robust communications than were capable with satellites.[32] Six months later Tim Berners-Lee would begin writing WorldWideWeb, the first web browser after two years of lobbying CERN management. By Christmas 1990, Berners-Lee had built all the tools necessary for a working Web: the HyperText Transfer Protocol (HTTP) 0.9,[33] the HyperText Markup Language (HTML), the first Web browser (which was also a HTML editor and could access Usenet newsgroups and FTP files), the first HTTP server software (later known as CERN httpd), the first web server,[34] and the first Web pages that described the project itself. In 1991 the Commercial Internet eXchange was founded, allowing PSInet to communicate with the other commercial networks CERFnet and Alternet. Stanford Federal Credit Union was the first financial institution to offer online Internet banking services to all of its members in October 1994.[35] In 1996 OP Financial Group, also a cooperative bank, became the second online bank in the world and the first in Europe.[36] By 1995, the Internet was fully commercialized in the U.S. when the NSFNet was decommissioned, removing the last restrictions on use of the Internet to carry commercial traffic.[37]

World population[38]6.5 billion6.9 billion7.4 billion
Users worldwide16%30%48%
Users in the developing world8%21%41.3%
Users in the developed world51%67%81%
a Estimate.
Source: International Telecommunications Union.[39]

As technology advanced and commercial opportunities fueled reciprocal growth, the volume of Internet traffic started experiencing similar characteristics as that of the scaling of MOS transistors, exemplified by Moore’s law, doubling every 18 months. This growth, formalized as Edholm’s law, was catalyzed by advances in MOS technologylaser lightwave systems, and noise performance.[40]

Since 1995, the Internet has tremendously impacted culture and commerce, including the rise of near instant communication by email, instant messaging, telephony (Voice over Internet Protocol or VoIP), two-way interactive video calls, and the World Wide Web[41] with its discussion forums, blogs, social networking, and online shopping sites. Increasing amounts of data are transmitted at higher and higher speeds over fiber optic networks operating at 1-Gbit/s, 10-Gbit/s, or more. The Internet continues to grow, driven by ever greater amounts of online information and knowledge, commerce, entertainment and social networking.[42] During the late 1990s, it was estimated that traffic on the public Internet grew by 100 percent per year, while the mean annual growth in the number of Internet users was thought to be between 20% and 50%.[43] This growth is often attributed to the lack of central administration, which allows organic growth of the network, as well as the non-proprietary nature of the Internet protocols, which encourages vendor interoperability and prevents any one company from exerting too much control over the network.[44] As of 31 March 2011, the estimated total number of Internet users was 2.095 billion (30.2% of world population).[45] It is estimated that in 1993 the Internet carried only 1% of the information flowing through two-way telecommunication, by 2000 this figure had grown to 51%, and by 2007 more than 97% of all telecommunicated information was carried over the Internet.[46]


Main article: Internet governanceICANN headquarters in the Playa Vista neighborhood of Los Angeles, California, United States.

The Internet is a global network that comprises many voluntarily interconnected autonomous networks. It operates without a central governing body. The technical underpinning and standardization of the core protocols (IPv4 and IPv6) is an activity of the Internet Engineering Task Force (IETF), a non-profit organization of loosely affiliated international participants that anyone may associate with by contributing technical expertise. To maintain interoperability, the principal name spaces of the Internet are administered by the Internet Corporation for Assigned Names and Numbers (ICANN). ICANN is governed by an international board of directors drawn from across the Internet technical, business, academic, and other non-commercial communities. ICANN coordinates the assignment of unique identifiers for use on the Internet, including domain names, Internet Protocol (IP) addresses, application port numbers in the transport protocols, and many other parameters. Globally unified name spaces are essential for maintaining the global reach of the Internet. This role of ICANN distinguishes it as perhaps the only central coordinating body for the global Internet.[47]

Regional Internet registries (RIRs) were established for five regions of the world. The African Network Information Center (AfriNIC) for Africa, the American Registry for Internet Numbers (ARIN) for North America, the Asia-Pacific Network Information Centre (APNIC) for Asia and the Pacific region, the Latin American and Caribbean Internet Addresses Registry (LACNIC) for Latin America and the Caribbean region, and the Réseaux IP Européens – Network Coordination Centre (RIPE NCC) for Europe, the Middle East, and Central Asia were delegated to assign Internet Protocol address blocks and other Internet parameters to local registries, such as Internet service providers, from a designated pool of addresses set aside for each region.

The National Telecommunications and Information Administration, an agency of the United States Department of Commerce, had final approval over changes to the DNS root zone until the IANA stewardship transition on 1 October 2016.[48][49][50][51] The Internet Society (ISOC) was founded in 1992 with a mission to “assure the open development, evolution and use of the Internet for the benefit of all people throughout the world”.[52] Its members include individuals (anyone may join) as well as corporations, organizations, governments, and universities. Among other activities ISOC provides an administrative home for a number of less formally organized groups that are involved in developing and managing the Internet, including: the Internet Engineering Task Force (IETF), Internet Architecture Board (IAB), Internet Engineering Steering Group (IESG), Internet Research Task Force (IRTF), and Internet Research Steering Group (IRSG). On 16 November 2005, the United Nations-sponsored World Summit on the Information Society in Tunis established the Internet Governance Forum (IGF) to discuss Internet-related issues.


See also: List of countries by number of Internet users and List of countries by Internet connection speeds2007 map showing submarine fiberoptic telecommunication cables around the world.

The communications infrastructure of the Internet consists of its hardware components and a system of software layers that control various aspects of the architecture. As with any computer network, the Internet physically consists of routers, media (such as cabling and radio links), repeaters, modems etc. However, as an example of internetworking, many of the network nodes are not necessarily internet equipment per se, the internet packets are carried by other full-fledged networking protocols with the Internet acting as a homogeneous networking standard, running across heterogeneous hardware, with the packets guided to their destinations by IP routers.

Routing and service tiers

Packet routing across the Internet involves several tiers of Internet service providers.

Internet service providers (ISPs) establish the worldwide connectivity between individual networks at various levels of scope. End-users who only access the Internet when needed to perform a function or obtain information, represent the bottom of the routing hierarchy. At the top of the routing hierarchy are the tier 1 networks, large telecommunication companies that exchange traffic directly with each other via very high speed fibre optic cables and governed by peering agreements. Tier 2 and lower level networks buy Internet transit from other providers to reach at least some parties on the global Internet, though they may also engage in peering. An ISP may use a single upstream provider for connectivity, or implement multihoming to achieve redundancy and load balancing. Internet exchange points are major traffic exchanges with physical connections to multiple ISPs. Large organizations, such as academic institutions, large enterprises, and governments, may perform the same function as ISPs, engaging in peering and purchasing transit on behalf of their internal networks. Research networks tend to interconnect with large subnetworks such as GEANTGLORIADInternet2, and the UK’s national research and education networkJANET. Both the Internet IP routing structure and hypertext links of the World Wide Web are examples of scale-free networks.[53][disputed (for: unclear whether citation supports claim empirically)  – discuss] Computers and routers use routing tables in their operating system to direct IP packets to the next-hop router or destination. Routing tables are maintained by manual configuration or automatically by routing protocols. End-nodes typically use a default route that points toward an ISP providing transit, while ISP routers use the Border Gateway Protocol to establish the most efficient routing across the complex connections of the global Internet.

An estimated 70 percent of the world’s Internet traffic passes through AshburnVirginia.[54][55][56][57]


Common methods of Internet access by users include dial-up with a computer modem via telephone circuits, broadband over coaxial cablefiber optics or copper wires, Wi-Fisatellite, and cellular telephone technology (e.g. 3G4G). The Internet may often be accessed from computers in libraries and Internet cafesInternet access points exist in many public places such as airport halls and coffee shops. Various terms are used, such as public Internet kioskpublic access terminal, and Web payphone. Many hotels also have public terminals that are usually fee-based. These terminals are widely accessed for various usages, such as ticket booking, bank deposit, or online payment. Wi-Fi provides wireless access to the Internet via local computer networks. Hotspots providing such access include Wi-Fi cafes, where users need to bring their own wireless devices such as a laptop or PDA. These services may be free to all, free to customers only, or fee-based.

Grassroots efforts have led to wireless community networks. Commercial Wi-Fi services that cover large areas are available in many cities, such as New YorkLondonViennaTorontoSan FranciscoPhiladelphiaChicago and Pittsburgh, where the Internet can then be accessed from places such as a park bench.[58] Experiments have also been conducted with proprietary mobile wireless networks like Ricochet, various high-speed data services over cellular networks, and fixed wireless services. Modern smartphones can also access the Internet through the cellular carrier network. For Web browsing, these devices provide applications such as Google ChromeSafari, and Firefox and a wide variety of other Internet software may be installed from app-stores. Internet usage by mobile and tablet devices exceeded desktop worldwide for the first time in October 2016.[59]

Mobile communication

Number of mobile cellular subscriptions 2012–2016, World Trends in Freedom of Expression and Media Development Global Report 2017/2018

The International Telecommunication Union (ITU) estimated that, by the end of 2017, 48% of individual users regularly connect to the Internet, up from 34% in 2012.[60] Mobile Internet connectivity has played an important role in expanding access in recent years especially in Asia and the Pacific and in Africa.[61] The number of unique mobile cellular subscriptions increased from 3.89 billion in 2012 to 4.83 billion in 2016, two-thirds of the world’s population, with more than half of subscriptions located in Asia and the Pacific. The number of subscriptions is predicted to rise to 5.69 billion users in 2020.[62] As of 2016, almost 60% of the world’s population had access to a 4G broadband cellular network, up from almost 50% in 2015 and 11% in 2012[disputed – discuss].[62] The limits that users face on accessing information via mobile applications coincide with a broader process of fragmentation of the Internet. Fragmentation restricts access to media content and tends to affect poorest users the most.[61]

Zero-rating, the practice of Internet service providers allowing users free connectivity to access specific content or applications without cost, has offered opportunities to surmount economic hurdles, but has also been accused by its critics as creating a two-tiered Internet. To address the issues with zero-rating, an alternative model has emerged in the concept of ‘equal rating’ and is being tested in experiments by Mozilla and Orange in Africa. Equal rating prevents prioritization of one type of content and zero-rates all content up to a specified data cap. A study published by Chatham House, 15 out of 19 countries researched in Latin America had some kind of hybrid or zero-rated product offered. Some countries in the region had a handful of plans to choose from (across all mobile network operators) while others, such as Colombia, offered as many as 30 pre-paid and 34 post-paid plans.[63]

A study of eight countries in the Global South found that zero-rated data plans exist in every country, although there is a great range in the frequency with which they are offered and actually used in each.[64] The study looked at the top three to five carriers by market share in Bangladesh, Colombia, Ghana, India, Kenya, Nigeria, Peru and Philippines.</ref> Across the 181 plans examined, 13 per cent were offering zero-rated services. Another study, covering GhanaKenyaNigeria and South Africa, found Facebook‘s Free Basics and Wikipedia Zero to be the most commonly zero-rated content.[65]

Internet Protocol Suite

Internet protocol suite
Application layer
Transport layer
Internet layer
Link layer

The Internet standards describe a framework known as the Internet protocol suite (also called TCP/IP, based on the first two components.) This is a model architecture that divides methods into a layered system of protocols, originally documented in RFC 1122 and RFC 1123.


The software layers correspond to the environment or scope in which their services operate. At the top is the application layer, space for the application-specific networking methods used in software applications. For example, a web browser program uses the client-server application model and a specific protocol of interaction between servers and clients, while many file-sharing systems use a peer-to-peer paradigm.

Below this top layer, the transport layer connects applications on different hosts with a logical channel through the network with appropriate data exchange methods. It provides several services including ordered, reliable delivery (TCP), and an unreliable datagram service (UDP).

Underlying these layers are the networking technologies that interconnect networks at their borders and exchange traffic across them. The Internet layer implements the Internet Protocol which enables computers to identify and locate each other by Internet Protocol (IP) addresses, and route their traffic via intermediate (transit) networks.[66] The internet protocol layer code is independent of the type of network that it is physically running over.

At the bottom of the architecture is the link layer, which provides logical connectivity between hosts. The link layer code is usually the only software part customized to the type of physical networking link protocol. Many link layers have been implemented and each operates over a type of network link, such as within a local area network (LAN) or wide area network (e.g. Wi-Fi or Ethernet or a dial-up connectionATM etc.).As user data is processed through the protocol stack, each abstraction layer adds encapsulation information at the sending host. Data is transmitted over the wire at the link level between hosts and routers. Encapsulation is removed by the receiving host. Intermediate relays update link encapsulation at each hop, and inspect the IP layer for routing purposes.

Internet protocol

Conceptual data flow in a simple network topology of two hosts (A and B) connected by a link between their respective routers. The application on each host executes read and write operations as if the processes were directly connected to each other by some kind of data pipe. After establishment of this pipe, most details of the communication are hidden from each process, as the underlying principles of communication are implemented in the lower protocol layers. In analogy, at the transport layer the communication appears as host-to-host, without knowledge of the application data structures and the connecting routers, while at the internetworking layer, individual network boundaries are traversed at each router.

The most prominent component of the Internet model is the Internet Protocol (IP). IP enables internetworking and, in essence, establishes the Internet itself. Two versions of the Internet Protocol exist, IPV4 and IPV6.

IP Addresses

A DNS resolver consults three name servers to resolve the domain name user-visible “www.wikipedia.org” to determine the IPV4 Address

For locating individual computers on the network, the Internet provides IP addresses. IP addresses are used by the Internet infrastructure to direct internet packets to their destinations. They consist of fixed-length numbers, which are found within the packet. IP addresses are generally assigned to equipment either automatically via DHCP, or are configured.

However the network also supports other addressing systems. Users generally enter domain names (e.g. “en.wikipedia.org”) instead of IP addresses because they are easier to remember, they are converted by the Domain Name System (DNS) into IP addresses which are more efficient for routing purposes.


Internet Protocol version 4 (IPv4) defines an IP address as a 32-bit number.[67] Internet Protocol Version 4 (IPv4) is the initial version used on the first generation of the Internet and is still in dominant use. It was designed to address up to ≈4.3 billion (109) hosts. However, the explosive growth of the Internet has led to IPv4 address exhaustion, which entered its final stage in 2011,[68] when the global IPv4 address allocation pool was exhausted.


Because of the growth of the Internet and the depletion of available IPv4 addresses, a new version of IP IPv6, was developed in the mid-1990s, which provides vastly larger addressing capabilities and more efficient routing of Internet traffic. IPv6 uses 128 bits for the IP address and was standardized in 1998.[69][70][71] IPv6 deployment has been ongoing since the mid-2000s. IPv6 is currently in growing deployment around the world, since Internet address registries (RIRs) began to urge all resource managers to plan rapid adoption and conversion.[72]

IPv6 is not directly interoperable by design with IPv4. In essence, it establishes a parallel version of the Internet not directly accessible with IPv4 software. Thus, translation facilities must exist for internetworking or nodes must have duplicate networking software for both networks. Essentially all modern computer operating systems support both versions of the Internet Protocol. Network infrastructure, however, has been lagging in this development. Aside from the complex array of physical connections that make up its infrastructure, the Internet is facilitated by bi- or multi-lateral commercial contracts, e.g., peering agreements, and by technical specifications or protocols that describe the exchange of data over the network. Indeed, the Internet is defined by its interconnections and routing policies.


Creating a subnet by dividing the host identifier

subnetwork or subnet is a logical subdivision of an IP network.[73]:1,16 The practice of dividing a network into two or more networks is called subnetting.

Computers that belong to a subnet are addressed with an identical most-significant bit-group in their IP addresses. This results in the logical division of an IP address into two fields, the network number or routing prefix and the rest field or host identifier. The rest field is an identifier for a specific host or network interface.

The routing prefix may be expressed in Classless Inter-Domain Routing (CIDR) notation written as the first address of a network, followed by a slash character (/), and ending with the bit-length of the prefix. For example, is the prefix of the Internet Protocol version 4 network starting at the given address, having 24 bits allocated for the network prefix, and the remaining 8 bits reserved for host addressing. Addresses in the range to belong to this network. The IPv6 address specification 2001:db8::/32 is a large address block with 296 addresses, having a 32-bit routing prefix.

For IPv4, a network may also be characterized by its subnet mask or netmask, which is the bitmask that when applied by a bitwise AND operation to any IP address in the network, yields the routing prefix. Subnet masks are also expressed in dot-decimal notation like an address. For example, is the subnet mask for the prefix

Traffic is exchanged between subnetworks through routers when the routing prefixes of the source address and the destination address differ. A router serves as a logical or physical boundary between the subnets.

The benefits of subnetting an existing network vary with each deployment scenario. In the address allocation architecture of the Internet using CIDR and in large organizations, it is necessary to allocate address space efficiently. Subnetting may also enhance routing efficiency, or have advantages in network management when subnetworks are administratively controlled by different entities in a larger organization. Subnets may be arranged logically in a hierarchical architecture, partitioning an organization’s network address space into a tree-like routing structure.


While the hardware components in the Internet infrastructure can often be used to support other software systems, it is the design and the standardization process of the software that characterizes the Internet and provides the foundation for its scalability and success. The responsibility for the architectural design of the Internet software systems has been assumed by the Internet Engineering Task Force (IETF).[74] The IETF conducts standard-setting work groups, open to any individual, about the various aspects of Internet architecture. Resulting contributions and standards are published as Request for Comments (RFC) documents on the IETF web site. The principal methods of networking that enable the Internet are contained in specially designated RFCs that constitute the Internet Standards. Other less rigorous documents are simply informative, experimental, or historical, or document the best current practices (BCP) when implementing Internet technologies.

Applications and services

The Internet carries many applications and services, most prominently the World Wide Web, including social mediaelectronic mailmobile applicationsmultiplayer online gamesInternet telephonyfile sharing, and streaming media services.

Most servers that provide these services are today hosted in data centers, and content is often accessed through high-performance content delivery networks.

World Wide Web

This NeXT Computer was used by Tim Berners-Lee at CERN and became the world’s first Web server.

The World Wide Web is a global collection of documentsimagesmultimedia, applications, and other resources, logically interrelated by hyperlinks and referenced with Uniform Resource Identifiers (URIs), which provide a global system of named references. URIs symbolically identify services, web servers, databases, and the documents and resources that they can provide. Hypertext Transfer Protocol (HTTP) is the main access protocol of the World Wide Web. Web services also use HTTP for communication between software systems for information transfer, sharing and exchanging business data and logistic and is one of many languages or protocols that can be used for communication on the Internet.[75]

World Wide Web browser software, such as Microsoft‘s Internet Explorer/EdgeMozilla FirefoxOperaApple‘s Safari, and Google Chrome, lets users navigate from one web page to another via the hyperlinks embedded in the documents. These documents may also contain any combination of computer data, including graphics, sounds, textvideomultimedia and interactive content that runs while the user is interacting with the page. Client-side software can include animations, gamesoffice applications and scientific demonstrations. Through keyword-driven Internet research using search engines like Yahoo!Bing and Google, users worldwide have easy, instant access to a vast and diverse amount of online information. Compared to printed media, books, encyclopedias and traditional libraries, the World Wide Web has enabled the decentralization of information on a large scale.

The Web has enabled individuals and organizations to publish ideas and information to a potentially large audience online at greatly reduced expense and time delay. Publishing a web page, a blog, or building a website involves little initial cost and many cost-free services are available. However, publishing and maintaining large, professional web sites with attractive, diverse and up-to-date information is still a difficult and expensive proposition. Many individuals and some companies and groups use web logs or blogs, which are largely used as easily updatable online diaries. Some commercial organizations encourage staff to communicate advice in their areas of specialization in the hope that visitors will be impressed by the expert knowledge and free information, and be attracted to the corporation as a result.

Advertising on popular web pages can be lucrative, and e-commerce, which is the sale of products and services directly via the Web, continues to grow. Online advertising is a form of marketing and advertising which uses the Internet to deliver promotional marketing messages to consumers. It includes email marketing, search engine marketing (SEM), social media marketing, many types of display advertising (including web banner advertising), and mobile advertising. In 2011, Internet advertising revenues in the United States surpassed those of cable television and nearly exceeded those of broadcast television.[76]:19 Many common online advertising practices are controversial and increasingly subject to regulation.

When the Web developed in the 1990s, a typical web page was stored in completed form on a web server, formatted in HTML, complete for transmission to a web browser in response to a request. Over time, the process of creating and serving web pages has become dynamic, creating a flexible design, layout, and content. Websites are often created using content management software with, initially, very little content. Contributors to these systems, who may be paid staff, members of an organization or the public, fill underlying databases with content using editing pages designed for that purpose while casual visitors view and read this content in HTML form. There may or may not be editorial, approval and security systems built into the process of taking newly entered content and making it available to the target visitors.


Email is an important communications service available on the Internet. The concept of sending electronic text messages between parties in a way analogous to mailing letters or memos predates the creation of the Internet.[77][78] Pictures, documents, and other files are sent as email attachments. Emails can be cc-ed to multiple email addresses.

Internet telephony is another common communications service made possible by the creation of the Internet. VoIP stands for Voice-over-Internet Protocol, referring to the protocol that underlies all Internet communication. The idea began in the early 1990s with walkie-talkie-like voice applications for personal computers. In recent years many VoIP systems have become as easy to use and as convenient as a normal telephone. The benefit is that, as the Internet carries the voice traffic, VoIP can be free or cost much less than a traditional telephone call, especially over long distances and especially for those with always-on Internet connections such as cable or ADSL and mobile data.[79] VoIP is maturing into a competitive alternative to traditional telephone service. Interoperability between different providers has improved and the ability to call or receive a call from a traditional telephone is available. Simple, inexpensive VoIP network adapters are available that eliminate the need for a personal computer.

Voice quality can still vary from call to call, but is often equal to and can even exceed that of traditional calls. Remaining problems for VoIP include emergency telephone number dialing and reliability. Currently, a few VoIP providers provide an emergency service, but it is not universally available. Older traditional phones with no “extra features” may be line-powered only and operate during a power failure; VoIP can never do so without a backup power source for the phone equipment and the Internet access devices. VoIP has also become increasingly popular for gaming applications, as a form of communication between players. Popular VoIP clients for gaming include Ventrilo and Teamspeak. Modern video game consoles also offer VoIP chat features.

Data transfer

File sharing is an example of transferring large amounts of data across the Internet. A computer file can be emailed to customers, colleagues and friends as an attachment. It can be uploaded to a website or File Transfer Protocol (FTP) server for easy download by others. It can be put into a “shared location” or onto a file server for instant use by colleagues. The load of bulk downloads to many users can be eased by the use of “mirror” servers or peer-to-peer networks. In any of these cases, access to the file may be controlled by user authentication, the transit of the file over the Internet may be obscured by encryption, and money may change hands for access to the file. The price can be paid by the remote charging of funds from, for example, a credit card whose details are also passed – usually fully encrypted – across the Internet. The origin and authenticity of the file received may be checked by digital signatures or by MD5 or other message digests. These simple features of the Internet, over a worldwide basis, are changing the production, sale, and distribution of anything that can be reduced to a computer file for transmission. This includes all manner of print publications, software products, news, music, film, video, photography, graphics and the other arts. This in turn has caused seismic shifts in each of the existing industries that previously controlled the production and distribution of these products.

Streaming media is the real-time delivery of digital media for the immediate consumption or enjoyment by end users. Many radio and television broadcasters provide Internet feeds of their live audio and video productions. They may also allow time-shift viewing or listening such as Preview, Classic Clips and Listen Again features. These providers have been joined by a range of pure Internet “broadcasters” who never had on-air licenses. This means that an Internet-connected device, such as a computer or something more specific, can be used to access on-line media in much the same way as was previously possible only with a television or radio receiver. The range of available types of content is much wider, from specialized technical webcasts to on-demand popular multimedia services. Podcasting is a variation on this theme, where – usually audio – material is downloaded and played back on a computer or shifted to a portable media player to be listened to on the move. These techniques using simple equipment allow anybody, with little censorship or licensing control, to broadcast audio-visual material worldwide.

Digital media streaming increases the demand for network bandwidth. For example, standard image quality needs 1 Mbit/s link speed for SD 480p, HD 720p quality requires 2.5 Mbit/s, and the top-of-the-line HDX quality needs 4.5 Mbit/s for 1080p.[80]

Webcams are a low-cost extension of this phenomenon. While some webcams can give full-frame-rate video, the picture either is usually small or updates slowly. Internet users can watch animals around an African waterhole, ships in the Panama Canal, traffic at a local roundabout or monitor their own premises, live and in real time. Video chat rooms and video conferencing are also popular with many uses being found for personal webcams, with and without two-way sound. YouTube was founded on 15 February 2005 and is now the leading website for free streaming video with a vast number of users. It uses a HTML5 based web player by default to stream and show video files.[81] Registered users may upload an unlimited amount of video and build their own personal profile. YouTube claims that its users watch hundreds of millions, and upload hundreds of thousands of videos daily.

Social impact

The Internet has enabled new forms of social interaction, activities, and social associations. This phenomenon has given rise to the scholarly study of the sociology of the Internet.


See also: Global Internet usageEnglish in computing, and Languages used on the InternetSee or edit source data.Share of population using the Internet[82]Internet users per 100 inhabitantsSource: International Telecommunications Union.[83][84]

Internet usage has grown tremendously. From 2000 to 2009, the number of Internet users globally rose from 394 million to 1.858 billion.[85] By 2010, 22 percent of the world’s population had access to computers with 1 billion Google searches every day, 300 million Internet users reading blogs, and 2 billion videos viewed daily on YouTube.[86] In 2014 the world’s Internet users surpassed 3 billion or 43.6 percent of world population, but two-thirds of the users came from richest countries, with 78.0 percent of Europe countries population using the Internet, followed by 57.4 percent of the Americas.[87] However, by 2018, this trend had shifted so tremendously that Asia alone accounted for 51% of all Internet users, with 2.2 billion out of the 4.3 billion Internet users in the world coming from that region. The number of China’s Internet users surpassed a major milestone in 2018, when the country’s Internet regulatory authority, China Internet Network Information Centre, announced that China had 802 million Internet users.[88] By 2019, China was the world’s leading country in terms of Internet users, with more than 800 million users, followed closely by India, with some 700 million users, with the United States a distant third with 275 million users. However, in terms of penetration, China has a 38.4% penetration rate compared to India’s 40% and the United States’s 80%.[89]

The prevalent language for communication via the Internet has always been English. This may be a result of the origin of the Internet, as well as the language’s role as a lingua franca and as a world language. Early computer systems were limited to the characters in the American Standard Code for Information Interchange (ASCII), a subset of the Latin alphabet.

After English (27%), the most requested languages on the World Wide Web are Chinese (25%), Spanish (8%), Japanese (5%), Portuguese and German (4% each), Arabic, French and Russian (3% each), and Korean (2%).[90] By region, 42% of the world’s Internet users are based in Asia, 24% in Europe, 14% in North America, 10% in Latin America and the Caribbean taken together, 6% in Africa, 3% in the Middle East and 1% in Australia/Oceania.[91] The Internet’s technologies have developed enough in recent years, especially in the use of Unicode, that good facilities are available for development and communication in the world’s widely used languages. However, some glitches such as mojibake (incorrect display of some languages’ characters) still remain.

In an American study in 2005, the percentage of men using the Internet was very slightly ahead of the percentage of women, although this difference reversed in those under 30. Men logged on more often, spent more time online, and were more likely to be broadband users, whereas women tended to make more use of opportunities to communicate (such as email). Men were more likely to use the Internet to pay bills, participate in auctions, and for recreation such as downloading music and videos. Men and women were equally likely to use the Internet for shopping and banking.[92] More recent studies indicate that in 2008, women significantly outnumbered men on most social networking sites, such as Facebook and Myspace, although the ratios varied with age.[93] In addition, women watched more streaming content, whereas men downloaded more.[94] In terms of blogs, men were more likely to blog in the first place; among those who blog, men were more likely to have a professional blog, whereas women were more likely to have a personal blog.[95]

Forecasts predict that 44% of the world’s population will be users of the Internet by 2020.[96] Splitting by country, in 2012 Iceland, Norway, Sweden, the Netherlands, and Denmark had the highest Internet penetration by the number of users, with 93% or more of the population with access.[97]

Several neologisms exist that refer to Internet users: Netizen (as in “citizen of the net”)[98] refers to those actively involved in improving online communities, the Internet in general or surrounding political affairs and rights such as free speech,[99][100] Internaut refers to operators or technically highly capable users of the Internet,[101][102] digital citizen refers to a person using the Internet in order to engage in society, politics, and government participation.[103]


Internet users in 2015 as a percentage of a country’s populationSource: International Telecommunications Union.[97]Main articles: Global digital divide and Digital divideFixed broadband Internet subscriptions in 2012
as a percentage of a country’s population
Source: International Telecommunications Union.[105]Mobile broadband Internet subscriptions in 2012
as a percentage of a country’s population
Source: International Telecommunications Union.[106]

The Internet allows greater flexibility in working hours and location, especially with the spread of unmetered high-speed connections. The Internet can be accessed almost anywhere by numerous means, including through mobile Internet devices. Mobile phones, datacardshandheld game consoles and cellular routers allow users to connect to the Internet wirelessly. Within the limitations imposed by small screens and other limited facilities of such pocket-sized devices, the services of the Internet, including email and the web, may be available. Service providers may restrict the services offered and mobile data charges may be significantly higher than other access methods.

Educational material at all levels from pre-school to post-doctoral is available from websites. Examples range from CBeebies, through school and high-school revision guides and virtual universities, to access to top-end scholarly literature through the likes of Google Scholar. For distance education, help with homework and other assignments, self-guided learning, whiling away spare time, or just looking up more detail on an interesting fact, it has never been easier for people to access educational information at any level from anywhere. The Internet in general and the World Wide Web in particular are important enablers of both formal and informal education. Further, the Internet allows universities, in particular, researchers from the social and behavioral sciences, to conduct research remotely via virtual laboratories, with profound changes in reach and generalizability of findings as well as in communication between scientists and in the publication of results.[107]

The low cost and nearly instantaneous sharing of ideas, knowledge, and skills have made collaborative work dramatically easier, with the help of collaborative software. Not only can a group cheaply communicate and share ideas but the wide reach of the Internet allows such groups more easily to form. An example of this is the free software movement, which has produced, among other things, LinuxMozilla Firefox, and OpenOffice.org (later forked into LibreOffice). Internet chat, whether using an IRC chat room, an instant messaging system, or a social networking website, allows colleagues to stay in touch in a very convenient way while working at their computers during the day. Messages can be exchanged even more quickly and conveniently than via email. These systems may allow files to be exchanged, drawings and images to be shared, or voice and video contact between team members.

Content management systems allow collaborating teams to work on shared sets of documents simultaneously without accidentally destroying each other’s work. Business and project teams can share calendars as well as documents and other information. Such collaboration occurs in a wide variety of areas including scientific research, software development, conference planning, political activism and creative writing. Social and political collaboration is also becoming more widespread as both Internet access and computer literacy spread.

The Internet allows computer users to remotely access other computers and information stores easily from any access point. Access may be with computer security, i.e. authentication and encryption technologies, depending on the requirements. This is encouraging new ways of working from home, collaboration and information sharing in many industries. An accountant sitting at home can audit the books of a company based in another country, on a server situated in a third country that is remotely maintained by IT specialists in a fourth. These accounts could have been created by home-working bookkeepers, in other remote locations, based on information emailed to them from offices all over the world. Some of these things were possible before the widespread use of the Internet, but the cost of private leased lines would have made many of them infeasible in practice. An office worker away from their desk, perhaps on the other side of the world on a business trip or a holiday, can access their emails, access their data using cloud computing, or open a remote desktop session into their office PC using a secure virtual private network (VPN) connection on the Internet. This can give the worker complete access to all of their normal files and data, including email and other applications, while away from the office. It has been referred to among system administrators as the Virtual Private Nightmare,[108] because it extends the secure perimeter of a corporate network into remote locations and its employees’ homes.

Social networking and entertainment

See also: Social networking service § Social impact

Many people use the World Wide Web to access news, weather and sports reports, to plan and book vacations and to pursue their personal interests. People use chat, messaging and email to make and stay in touch with friends worldwide, sometimes in the same way as some previously had pen palsSocial networking websites such as FacebookTwitter, and Myspace have created new ways to socialize and interact. Users of these sites are able to add a wide variety of information to pages, to pursue common interests, and to connect with others. It is also possible to find existing acquaintances, to allow communication among existing groups of people. Sites like LinkedIn foster commercial and business connections. YouTube and Flickr specialize in users’ videos and photographs. While social networking sites were initially for individuals only, today they are widely used by businesses and other organizations to promote their brands, to market to their customers and to encourage posts to “go viral“. “Black hat” social media techniques are also employed by some organizations, such as spam accounts and astroturfing.

A risk for both individuals and organizations writing posts (especially public posts) on social networking websites, is that especially foolish or controversial posts occasionally lead to an unexpected and possibly large-scale backlash on social media from other Internet users. This is also a risk in relation to controversial offline behavior, if it is widely made known. The nature of this backlash can range widely from counter-arguments and public mockery, through insults and hate speech, to, in extreme cases, rape and death threats. The online disinhibition effect describes the tendency of many individuals to behave more stridently or offensively online than they would in person. A significant number of feminist women have been the target of various forms of harassment in response to posts they have made on social media, and Twitter in particular has been criticised in the past for not doing enough to aid victims of online abuse.[109]

For organizations, such a backlash can cause overall brand damage, especially if reported by the media. However, this is not always the case, as any brand damage in the eyes of people with an opposing opinion to that presented by the organization could sometimes be outweighed by strengthening the brand in the eyes of others. Furthermore, if an organization or individual gives in to demands that others perceive as wrong-headed, that can then provoke a counter-backlash.

Some websites, such as Reddit, have rules forbidding the posting of personal information of individuals (also known as doxxing), due to concerns about such postings leading to mobs of large numbers of Internet users directing harassment at the specific individuals thereby identified. In particular, the Reddit rule forbidding the posting of personal information is widely understood to imply that all identifying photos and names must be censored in Facebook screenshots posted to Reddit. However, the interpretation of this rule in relation to public Twitter posts is less clear, and in any case, like-minded people online have many other ways they can use to direct each other’s attention to public social media posts they disagree with.

Children also face dangers online such as cyberbullying and approaches by sexual predators, who sometimes pose as children themselves. Children may also encounter material which they may find upsetting, or material which their parents consider to be not age-appropriate. Due to naivety, they may also post personal information about themselves online, which could put them or their families at risk unless warned not to do so. Many parents choose to enable Internet filtering, and/or supervise their children’s online activities, in an attempt to protect their children from inappropriate material on the Internet. The most popular social networking websites, such as Facebook and Twitter, commonly forbid users under the age of 13. However, these policies are typically trivial to circumvent by registering an account with a false birth date, and a significant number of children aged under 13 join such sites anyway. Social networking sites for younger children, which claim to provide better levels of protection for children, also exist.[110]

The Internet has been a major outlet for leisure activity since its inception, with entertaining social experiments such as MUDs and MOOs being conducted on university servers, and humor-related Usenet groups receiving much traffic.[citation needed] Many Internet forums have sections devoted to games and funny videos.[citation needed] The Internet pornography and online gambling industries have taken advantage of the World Wide Web, and often provide a significant source of advertising revenue for other websites.[111] Although many governments have attempted to restrict both industries’ use of the Internet, in general, this has failed to stop their widespread popularity.[112]

Another area of leisure activity on the Internet is multiplayer gaming.[113] This form of recreation creates communities, where people of all ages and origins enjoy the fast-paced world of multiplayer games. These range from MMORPG to first-person shooters, from role-playing video games to online gambling. While online gaming has been around since the 1970s, modern modes of online gaming began with subscription services such as GameSpy and MPlayer.[114] Non-subscribers were limited to certain types of game play or certain games. Many people use the Internet to access and download music, movies and other works for their enjoyment and relaxation. Free and fee-based services exist for all of these activities, using centralized servers and distributed peer-to-peer technologies. Some of these sources exercise more care with respect to the original artists’ copyrights than others.

Internet usage has been correlated to users’ loneliness.[115] Lonely people tend to use the Internet as an outlet for their feelings and to share their stories with others, such as in the “I am lonely will anyone speak to me” thread.

The Internet consolidates most aspects of human endeavor into singular arenas of which all of humanity are potential members and competitors, with fundamentally negative impacts on mental health as a result. While successes in each field of activity are pervasively visible and trumpeted, they are reserved for an extremely thin sliver of the world’s most exceptional, leaving everyone else behind. Whereas, before the Internet, expectations of success in any field were supported by reasonable probabilities of achievement at the village, suburb, city or even state level, the same expectations in the Internet world are virtually certain to bring disappointment today: there is always someone else, somewhere on the planet, who can do better and take the now one-and-only top spot.[116]

Cybersectarianism is a new organizational form which involves: “highly dispersed small groups of practitioners that may remain largely anonymous within the larger social context and operate in relative secrecy, while still linked remotely to a larger network of believers who share a set of practices and texts, and often a common devotion to a particular leader. Overseas supporters provide funding and support; domestic practitioners distribute tracts, participate in acts of resistance, and share information on the internal situation with outsiders. Collectively, members and practitioners of such sects construct viable virtual communities of faith, exchanging personal testimonies and engaging in the collective study via email, on-line chat rooms, and web-based message boards.”[117] In particular, the British government has raised concerns about the prospect of young British Muslims being indoctrinated into Islamic extremism by material on the Internet, being persuaded to join terrorist groups such as the so-called “Islamic State“, and then potentially committing acts of terrorism on returning to Britain after fighting in Syria or Iraq.

Cyberslacking can become a drain on corporate resources; the average UK employee spent 57 minutes a day surfing the Web while at work, according to a 2003 study by Peninsula Business Services.[118] Internet addiction disorder is excessive computer use that interferes with daily life. Nicholas G. Carr believes that Internet use has other effects on individuals, for instance improving skills of scan-reading and interfering with the deep thinking that leads to true creativity.[119]

Electronic business

Electronic business (e-business) encompasses business processes spanning the entire value chain: purchasing, supply chain managementmarketingsalescustomer service, and business relationship. E-commerce seeks to add revenue streams using the Internet to build and enhance relationships with clients and partners. According to International Data Corporation, the size of worldwide e-commerce, when global business-to-business and -consumer transactions are combined, equate to $16 trillion for 2013. A report by Oxford Economics adds those two together to estimate the total size of the digital economy at $20.4 trillion, equivalent to roughly 13.8% of global sales.[120]

While much has been written of the economic advantages of Internet-enabled commerce, there is also evidence that some aspects of the Internet such as maps and location-aware services may serve to reinforce economic inequality and the digital divide.[121] Electronic commerce may be responsible for consolidation and the decline of mom-and-popbrick and mortar businesses resulting in increases in income inequality.[122][123][124]

Author Andrew Keen, a long-time critic of the social transformations caused by the Internet, has recently focused on the economic effects of consolidation from Internet businesses. Keen cites a 2013 Institute for Local Self-Reliance report saying brick-and-mortar retailers employ 47 people for every $10 million in sales while Amazon employs only 14. Similarly, the 700-employee room rental start-up Airbnb was valued at $10 billion in 2014, about half as much as Hilton Worldwide, which employs 152,000 people. At that time, transportation network company Uber employed 1,000 full-time employees and was valued at $18.2 billion, about the same valuation as Avis Rent a Car and The Hertz Corporation combined, which together employed almost 60,000 people.[125]


Telecommuting is the performance within a traditional worker and employer relationship when it is facilitated by tools such as groupwarevirtual private networksconference callingvideoconferencing, and voice over IP (VOIP) so that work may be performed from any location, most conveniently the worker’s home. It can be efficient and useful for companies as it allows workers to communicate over long distances, saving significant amounts of travel time and cost. As broadband Internet connections become commonplace, more workers have adequate bandwidth at home to use these tools to link their home to their corporate intranet and internal communication networks.

Collaborative publishing

Wikis have also been used in the academic community for sharing and dissemination of information across institutional and international boundaries.[126] In those settings, they have been found useful for collaboration on grant writingstrategic planning, departmental documentation, and committee work.[127] The United States Patent and Trademark Office uses a wiki to allow the public to collaborate on finding prior art relevant to examination of pending patent applications. Queens, New York has used a wiki to allow citizens to collaborate on the design and planning of a local park.[128] The English Wikipedia has the largest user base among wikis on the World Wide Web[129] and ranks in the top 10 among all Web sites in terms of traffic.[130]

Politics and political revolutions

See also: Internet censorshipMass surveillance, and Social media use in politicsBanner in Bangkok during the 2014 Thai coup d’état, informing the Thai public that ‘like’ or ‘share’ activities on social media could result in imprisonment (observed June 30, 2014).

The Internet has achieved new relevance as a political tool. The presidential campaign of Howard Dean in 2004 in the United States was notable for its success in soliciting donation via the Internet. Many political groups use the Internet to achieve a new method of organizing for carrying out their mission, having given rise to Internet activism, most notably practiced by rebels in the Arab Spring.[131][132] The New York Times suggested that social media websites, such as Facebook and Twitter, helped people organize the political revolutions in Egypt, by helping activists organize protests, communicate grievances, and disseminate information.[133]

Many have understood the Internet as an extension of the Habermasian notion of the public sphere, observing how network communication technologies provide something like a global civic forum. However, incidents of politically motivated Internet censorship have now been recorded in many countries, including western democracies.[citation needed]


The spread of low-cost Internet access in developing countries has opened up new possibilities for peer-to-peer charities, which allow individuals to contribute small amounts to charitable projects for other individuals. Websites, such as DonorsChoose and GlobalGiving, allow small-scale donors to direct funds to individual projects of their choice. A popular twist on Internet-based philanthropy is the use of peer-to-peer lending for charitable purposes. Kiva pioneered this concept in 2005, offering the first web-based service to publish individual loan profiles for funding. Kiva raises funds for local intermediary microfinance organizations which post stories and updates on behalf of the borrowers. Lenders can contribute as little as $25 to loans of their choice, and receive their money back as borrowers repay. Kiva falls short of being a pure peer-to-peer charity, in that loans are disbursed before being funded by lenders and borrowers do not communicate with lenders themselves.[134][135]

However, the recent spread of low-cost Internet access in developing countries has made genuine international person-to-person philanthropy increasingly feasible. In 2009, the US-based nonprofit Zidisha tapped into this trend to offer the first person-to-person microfinance platform to link lenders and borrowers across international borders without intermediaries. Members can fund loans for as little as a dollar, which the borrowers then use to develop business activities that improve their families’ incomes while repaying loans to the members with interest. Borrowers access the Internet via public cybercafes, donated laptops in village schools, and even smart phones, then create their own profile pages through which they share photos and information about themselves and their businesses. As they repay their loans, borrowers continue to share updates and dialogue with lenders via their profile pages. This direct web-based connection allows members themselves to take on many of the communication and recording tasks traditionally performed by local organizations, bypassing geographic barriers and dramatically reducing the cost of microfinance services to the entrepreneurs.[136]


Main article: Internet security

Internet resources, hardware, and software components are the target of criminal or malicious attempts to gain unauthorized control to cause interruptions, commit fraud, engage in blackmail or access private information.


Malware is malicious software used and distributed via the Internet. It includes computer viruses which are copied with the help of humans, computer worms which copy themselves automatically, software for denial of service attacksransomwarebotnets, and spyware that reports on the activity and typing of users. Usually, these activities constitute cybercrime. Defense theorists have also speculated about the possibilities of cyber warfare using similar methods on a large scale.[citation needed]


Main article: Computer and network surveillanceSee also: Signals intelligence and Mass surveillance

The vast majority of computer surveillance involves the monitoring of data and traffic on the Internet.[137] In the United States for example, under the Communications Assistance For Law Enforcement Act, all phone calls and broadband Internet traffic (emails, web traffic, instant messaging, etc.) are required to be available for unimpeded real-time monitoring by Federal law enforcement agencies.[138][139][140] Packet capture is the monitoring of data traffic on a computer network. Computers communicate over the Internet by breaking up messages (emails, images, videos, web pages, files, etc.) into small chunks called “packets”, which are routed through a network of computers, until they reach their destination, where they are assembled back into a complete “message” again. Packet Capture Appliance intercepts these packets as they are traveling through the network, in order to examine their contents using other programs. A packet capture is an information gathering tool, but not an analysis tool. That is it gathers “messages” but it does not analyze them and figure out what they mean. Other programs are needed to perform traffic analysis and sift through intercepted data looking for important/useful information. Under the Communications Assistance For Law Enforcement Act all U.S. telecommunications providers are required to install packet sniffing technology to allow Federal law enforcement and intelligence agencies to intercept all of their customers’ broadband Internet and voice over Internet protocol (VoIP) traffic.[141]

The large amount of data gathered from packet capturing requires surveillance software that filters and reports relevant information, such as the use of certain words or phrases, the access of certain types of web sites, or communicating via email or chat with certain parties.[142] Agencies, such as the Information Awareness OfficeNSAGCHQ and the FBI, spend billions of dollars per year to develop, purchase, implement, and operate systems for interception and analysis of data.[143] Similar systems are operated by Iranian secret police to identify and suppress dissidents. The required hardware and software was allegedly installed by German Siemens AG and Finnish Nokia.[144]


Main articles: Internet censorship and Internet freedomSee also: Culture of fear and Great FirewallInternet censorship and surveillance by country (2018)[145][146][147][148][149]

  Pervasive  Substantial  Selective  Little or none

  Unclassified / No data

Some governments, such as those of BurmaIranNorth KoreaMainland ChinaSaudi Arabia and the United Arab Emirates, restrict access to content on the Internet within their territories, especially to political and religious content, with domain name and keyword filters.[150]

In Norway, Denmark, Finland, and Sweden, major Internet service providers have voluntarily agreed to restrict access to sites listed by authorities. While this list of forbidden resources is supposed to contain only known child pornography sites, the content of the list is secret.[151] Many countries, including the United States, have enacted laws against the possession or distribution of certain material, such as child pornography, via the Internet, but do not mandate filter software. Many free or commercially available software programs, called content-control software are available to users to block offensive websites on individual computers or networks, in order to limit access by children to pornographic material or depiction of violence.


As the Internet is a heterogeneous network, the physical characteristics, including for example the data transfer rates of connections, vary widely. It exhibits emergent phenomena that depend on its large-scale organization.[152]

Traffic volume

Global Internet Traffic

The volume of Internet traffic is difficult to measure, because no single point of measurement exists in the multi-tiered, non-hierarchical topology. Traffic data may be estimated from the aggregate volume through the peering points of the Tier 1 network providers, but traffic that stays local in large provider networks may not be accounted for.


An Internet blackout or outage can be caused by local signalling interruptions. Disruptions of submarine communications cables may cause blackouts or slowdowns to large areas, such as in the 2008 submarine cable disruption. Less-developed countries are more vulnerable due to a small number of high-capacity links. Land cables are also vulnerable, as in 2011 when a woman digging for scrap metal severed most connectivity for the nation of Armenia.[153] Internet blackouts affecting almost entire countries can be achieved by governments as a form of Internet censorship, as in the blockage of the Internet in Egypt, whereby approximately 93%[154] of networks were without access in 2011 in an attempt to stop mobilization for anti-government protests.[155]

Energy use

In 2011, researchers estimated the energy used by the Internet to be between 170 and 307 GW, less than two percent of the energy used by humanity. This estimate included the energy needed to build, operate, and periodically replace the estimated 750 million laptops, a billion smart phones and 100 million servers worldwide as well as the energy that routers, cell towers, optical switches, Wi-Fi transmitters and cloud storage devices use when transmitting Internet traffic.[156][157] According to a study published in 2018, nearly 4% of global CO2 emission could be attributed to global data transfer and the necessary infrastructure.[158] The study also said that online video streaming alone accounted for 60% of this data transfer and therefore contributed to over 300 million tons of CO2 emission per year.[159]

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Laboratory mouse

From Wikipedia, the free encyclopedia
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An albino SCID laboratory mouse
A laboratory mouse with intermediate coat colour

The laboratory mouse is a small mammal of the order Rodentia which is bred and used for scientific research. Laboratory mice are usually of the species Mus musculus. They are the most commonly used mammalian research model and are used for research in geneticspsychologymedicine and other scientific disciplines. Mice belong to the Euarchontoglires clade, which includes humans. This close relationship, the associated high homology with humans, their ease of maintenance and handling, and their high reproduction rate, make mice particularly suitable models for human-oriented research. The laboratory mouse genome has been sequenced and many mouse genes have human homologues.[1]

Other mouse species sometimes used in laboratory research include the American white-footed mouse (Peromyscus leucopus) and the deer mouse (Peromyscus maniculatus).

History as a biological model[edit]

Mice have been used in biomedical research since the 17th Century (from May 30, 1678) when William Harvey used them for his studies on reproduction and blood circulation and Robert Hooke used them to investigate the biological consequences of an increase in air pressure.[2] During the 18th century Joseph Priestley and Antoine Lavoisier both used mice to study respiration. In the 19th century Gregor Mendel carried out his early investigations of inheritance on mouse coat color but was asked by his superior to stop breeding in his cell “smelly creatures that, in addition, copulated and had sex”.[2] He then switched his investigations to peas but, as his observations were published in a somewhat obscure botanical journal, they were virtually ignored for over 35 years until they were rediscovered in the early 20th century. In 1902 Lucien Cuénot published the results of his experiments using mice which showed that Mendel’s laws of inheritance were also valid for animals — results that were soon confirmed and extended to other species.[2]

In the early part of the 20th century, Harvard undergraduate Clarence Cook Little was conducting studies on mouse genetics in the laboratory of William Ernest Castle. Little and Castle collaborated closely with Abbie Lathrop who was a breeder of fancy mice and rats which she marketed to rodent hobbyists and keepers of exotic pets, and later began selling in large numbers to scientific researchers.[3] Together they generated the DBA (Dilute, Brown and non-Agouti) inbred mouse strain and initiated the systematic generation of inbred strains.[4] The mouse has since been used extensively as a model organism and is associated with many important biological discoveries of the 20th and 21st Centuries.[2]

The Jackson Laboratory in Bar Harbor, Maine is currently one of the world’s largest suppliers of laboratory mice, at around 3 million mice a year.[5] The laboratory is also the world’s source for more than 8,000 strains of genetically defined mice and is home of the Mouse Genome Informatics database.[6]


1 day old pups

Breeding onset occurs at about 50 days of age in both females and males, although females may have their first estrus at 25–40 days. Mice are polyestrous and breed year round; ovulation is spontaneous. The duration of the estrous cycle is 4–5 days and lasts about 12 hours, occurring in the evening. Vaginal smears are useful in timed matings to determine the stage of the estrous cycle. Mating can be confirmed by the presence of a copulatory plug in the vagina up to 24 hours post-copulation. The presence of sperm on a vaginal smear is also a reliable indicator of mating.[7]

The average gestation period is 20 days. A fertile postpartum estrus occurs 14–24 hours following parturition, and simultaneous lactation and gestation prolongs gestation by 3–10 days owing to delayed implantation. The average litter size is 10–12 during optimum production, but is highly strain-dependent. As a general rule, inbred mice tend to have longer gestation periods and smaller litters than outbred and hybrid mice. The young are called pups and weigh 0.5–1.5 g (0.018–0.053 oz) at birth, are hairless, and have closed eyelids and ears. Pups are weaned at 3 weeks of age when they weigh about 10–12 g (0.35–0.42 oz). If the female does not mate during the postpartum estrus, she resumes cycling 2–5 days post-weaning.[7]

Newborn males are distinguished from newborn females by noting the greater anogenital distance and larger genital papilla in the male. This is best accomplished by lifting the tails of littermates and comparing perinea.[7]

Genetics and strains[edit]

Mice are mammals of the clade (a group consisting of an ancestor and all its descendants) Euarchontoglires, which means they are amongst the closest non-primate relatives of humans along with lagomorphstreeshrews, and flying lemurs.


Rodentia (rodents)

Lagomorpha (rabbits, hares, pikas)


Scandentia (treeshrews)


Dermoptera (flying lemurs)

Primates (†PlesiadapiformesStrepsirrhiniHaplorrhini)

Laboratory mice are the same species as the house mouse, however, they are often very different in behaviour and physiology. There are hundreds of established inbredoutbred, and transgenic strains. A strain, in reference to rodents, is a group in which all members are as nearly as possible genetically identical. In laboratory mice, this is accomplished through inbreeding. By having this type of population, it is possible to conduct experiments on the roles of genes, or conduct experiments that exclude genetic variation as a factor. In contrast, outbred populations are used when identical genotypes are unnecessary or a population with genetic variation is required, and are usually referred to as stocks rather than strains.[8][9] Over 400 standardized, inbred strains have been developed.[citation needed]

Most laboratory mice are hybrids of different subspecies, most commonly of Mus musculus domesticus and Mus musculus musculus. Laboratory mice can have a variety of coat colours, including agouti, black and albino. Many (but not all) laboratory strains are inbred. The different strains are identified with specific letter-digit combinations; for example C57BL/6 and BALB/c. The first such inbred strains were produced in 1909 by Clarence Cook Little, who was influential in promoting the mouse as a laboratory organism.[10] In 2011, an estimated 83% of laboratory rodents supplied in the U.S. were C57BL/6 laboratory mice.[11]


Sequencing of the laboratory mouse genome was completed in late 2002 using the C57BL/6 strain. This was only the second mammalian genome to be sequenced after humans.[11] The haploid genome is about three billion base pairs long (3,000 Mb distributed over 19 autosomal chromosomes plus 1 respectively 2 sex chromosomes), therefore equal to the size of the human genome. Estimating the number of genes contained in the mouse genome is difficult, in part because the definition of a gene is still being debated and extended. The current count of primary coding genes in the laboratory mouse is 23,139.[12] compared to an estimated 20,774 in humans.[12]

Mutant and transgenic strains[edit]

Two mice expressing enhanced green fluorescent protein under UV-illumination flanking one plain mouse from the non-transgenic parental line.
Comparison of a knockout Obese mouse (left) and a normal laboratory mouse (right).

Various mutant strains of mice have been created by a number of methods. A small selection from the many available strains includes –

Since 1998, it has been possible to clone mice from cells derived from adult animals.

Appearance and behaviour[edit]

Laboratory mice have retained many of the physical and behavioural characteristics of house mice, however, due to many generations of artificial selection some of these characteristics now vary markedly. Due to the large number of strains of laboratory mice, it is impractical to comprehensively describe the appearance and behaviour of all these, however, they are described below for two of the most commonly used strains.


A female C57BL/6 laboratory mouse

C57BL/6 mice have a dark brown, nearly black coat. They are more sensitive to noise and odours and are more likely to bite than the more docile laboratory strains such as BALB/c.[14]

Group-housed C57BL/6 mice (and other strains) display barbering behaviour, in which the dominant mouse in a cage selectively removes hair from its subordinate cage mates.[15] Mice that have been barbered extensively can have large bald patches on their bodies, commonly around the head, snout, and shoulders, although barbering may appear anywhere on the body. Both hair and vibrissae may be removed. Barbering is more frequently seen in female mice; male mice are more likely to display dominance through fighting.[16]

C57BL/6 has several unusual characteristics which make it useful for some research studies but inappropriate for others: It is unusually sensitive to pain and to cold, and analgesic medications are less effective in this strain.[17] Unlike most laboratory mouse strains, the C57BL/6 drinks alcoholic beverages voluntarily. It is more susceptible than average to morphine addictionatherosclerosis, and age-related hearing loss.[11]


BALB/c laboratory mice

BALB/c is an albino, laboratory-bred strain from which a number of common substrains are derived. With over 200 generations bred since 1920, BALB/c mice are distributed globally and are among the most widely used inbred strains used in animal experimentation.[18]

BALB/c are noted for displaying high levels of anxiety and for being relatively resistant to diet-induced atherosclerosis, making them a useful model for cardiovascular research.[19][20]

Male BALB/c mice are aggressive and will fight other males if housed together. However, the BALB/Lac substrain is much more docile.[21] Most BALB/c mice substrains have a long reproductive life-span.[18]

There are noted differences between different BALB/c substrains, though these are thought to be due to mutation rather than genetic contamination.[22] The BALB/cWt is unusual in that 3% of progeny display true hermaphroditism.[23]


Laboratory mouse (note the ear tag)


Traditionally, laboratory mice have been picked up by the base of the tail. However, recent research has shown that this type of handling increases anxiety and aversive behaviour.[24] Instead, handling mice using a tunnel or cupped hands is advocated. In behavioural tests, tail-handled mice show less willingness to explore and to investigate test stimuli, as opposed to tunnel-handled mice which readily explore and show robust responses to test stimuli.[25]


In nature, mice are usually herbivores, consuming a wide range of fruit or grain.[26] However, in laboratory studies it is usually necessary to avoid biological variation and to achieve this, laboratory mice are almost always fed only commercial pelleted mouse feed. Food intake is approximately 15 g (0.53 oz) per 100 g (3.5 oz) of body weight per day; water intake is approximately 15 ml (0.53 imp fl oz; 0.51 US fl oz) per 100 g of body weight per day.[7]

Injection procedures[edit]

Routes of administration of injections in laboratory mice are mainly subcutaneousintraperitoneal and intravenousIntramuscular administration is not recommended due to small muscle mass.[27] Intracerebral administration is also possible. Each route has a recommended injection site, approximate needle gauge and recommended maximum injected volume at a single time at one site, as given in the table below:

RouteRecommended site[27]Needle gauge[27]Maximal volume[28]
subcutaneousdorsum, between scapula25-26 ga2-3 ml
intraperitonealleft lower quadrant25-27 ga2-3 ml
intravenouslateral tail vein27-28 ga0.2 ml
intramuscularhindlimb, caudal thigh26-27 ga0.05 ml
intracerebralcranium27 ga

To facilitate intravenous injection into the tail, laboratory mice can be carefully warmed under heat lamps to vasodilate the vessels.[27]


A common regimen for general anesthesia for the house mouse is ketamine (in the dose of 100 mg per kg body weight) plus xylazine (in the dose of 5–10 mg per kg), injected by the intraperitoneal route.[29] It has a duration of effect of about 30 minutes.[29]


Approved procedures for euthanasia of laboratory mice include compressed CO
 gas, injectable barbiturate anesthetics, inhalable anesthetics, such as Halothane, and physical methods, such as cervical dislocation and decapitation.[30] In 2013, the American Veterinary Medical Association issued new guidelines for CO
 induction, stating that a flow rate of 10% to 30% volume/min is optimal for euthanasing laboratory mice.[31]

Pathogen susceptibility[edit]

A recent study detected a murine astrovirus in laboratory mice held at more than half of the US and Japanese institutes investigated.[32] Murine astrovirus was found in nine mice strains, including NSGNOD-SCIDNSG-3GSC57BL6Timp-3−/−uPA-NOGB6J, ICR, Bash2, and BALB/C, with various degrees of prevalence. The pathogenicity of the murine astrovirus was not known.

Legislation in research[edit]

United Kingdom[edit]

In the UK, as with all other vertebrates and some invertebrates, any scientific procedure which is likely to cause “pain, suffering, distress or lasting harm” is regulated by the Home Office under the Animals (Scientific Procedures) Act 1986. UK regulations are considered amongst the most comprehensive and rigorous in the world.[33] Detailed data on the use of laboratory mice (and other species) in research in the UK are published each year.[34] In the UK in 2013, there were a total of 3,077,115 regulated procedures on mice in scientific procedure establishments, licensed under the Act.[35]

United States[edit]

In the US, laboratory mice are not regulated under the Animal Welfare Act administered by the USDA APHIS. However, the Public Health Service Act (PHS) as administered by the National Institutes of Health does offer a standard for their care and use. Compliance with the PHS is required for a research project to receive federal funding. PHS policy is administered by the Office of Laboratory Animal Welfare. Many academic research institutes seek accreditation voluntarily, often through the Association for Assessment and Accreditation of Laboratory Animal Care, which maintains the standards of care found within The Guide for the Care and Use of Laboratory Animals and the PHS policy. This accreditation is however not a prerequisite for federal funding, unlike the actual compliance.[36]


While mice are by far the most widely used animals in biomedical research, recent studies have highlighted their limitations.[37] For example, the utility of rodents in testing for sepsis,[38] burns,[38] inflammation,[38] stroke,[39][40] ALS,[41][42][43] Alzheimer’s disease,[44] diabetes,[45][46] cancer,[47][48][49][50][51] multiple sclerosis,[52] Parkinson’s disease,[52] and other illnesses has been called into question by a number of researchers. Regarding experiments on mice, some researchers have complained that “years and billions of dollars have been wasted following false leads” as a result of a preoccupation with the use of these animals in studies.[37]

An article in The Scientist notes, “The difficulties associated with using animal models for human disease result from the metabolic, anatomic, and cellular differences between humans and other creatures, but the problems go even deeper than that” including issues with the design and execution of the tests themselves.[40]

For example, researchers have found that many mice in laboratories are obese from excess food and minimal exercise which alters their physiology and drug metabolism.[53] Many laboratory animals, including mice, are chronically stressed which can also negatively affect research outcomes and the ability to accurately extrapolate findings to humans.[54][55] Researchers have also noted that many studies involving mice are poorly designed, leading to questionable findings.[40][42][43]

Some studies suggests that inadequate published data in animal testing may result in irreproducible research, with missing details about how experiments are done are omitted from published papers or differences in testing that may introduce bias. Examples of hidden bias include a 2014 study from McGill University which suggests that mice handled by men rather than women showed higher stress levels.[5][56][57] Another study in 2016 suggested that gut microbiomes in mice may have an impact upon scientific research.[58]

Market size[edit]

The world-wide market for gene-altered mice is predicted to grow to $1.59 billion by 2022, growing at a rate of 7.5 percent per year.[59]

See also[edit]


  1. ^ “MGI — Biology of the Laboratory Mouse”. Informatics.jax.org. Retrieved 29 July 2010.
  2. Jump up to:a b c d Hedrich, Hans, ed. (2004-08-21). “The house mouse as a laboratory model: a historical perspective”. The Laboratory Mouse. Elsevier Science. ISBN 9780080542539.
  3. ^ Steensma, David P.; Kyle, Robert A.; Shampo, Marc A. (November 2010). “Abbie Lathrop, the “Mouse Woman of Granby”: Rodent Fancier and Accidental Genetics Pioneer”Mayo Clinic Proceedings85 (11): e83. doi:10.4065/mcp.2010.0647PMC 2966381PMID 21061734.
  4. ^ Pillai, Shiv. “History of Immunology at Harvard”Immunology.HMS.Harvard.edu. Harvard Medical School. Retrieved 19 December 2013.
  5. Jump up to:a b “The world’s favourite lab animal has been found wanting, but there are new twists in the mouse’s tale”The Economist. Retrieved 10 January 2017.
  6. ^ “JAX Mice and Research Services”CRiver.com. Charles River Laboratories. 2016. Archived from the original on 18 August 2015. Retrieved 10 January 2016.
  7. Jump up to:a b c d Louisiana Veterinary Medical Association Archived 2012-08-03 at Archive.today
  8. ^ “Rules and guidelines for nomenclature of mouse and rat strains”.
  9. ^ “Outbred stocks”.
  10. ^ Crow, J. F. (August 2002). “C. C. Little, cancer and inbred mice”Genetics161 (4): 1357–61. PMC 1462216PMID 12196385.
  11. Jump up to:a b c Engber, D. (2011). “The trouble with Black-6”Slate. Retrieved 19 November 2013.
  12. Jump up to:a b “Mouse assembly and gene annotation”Ensembl. Retrieved 29 July 2013.
  13. ^ “JAX Mice Database — 002983 MRL.CBAJms-Fas/J”Jaxmice.jax.org. Bar Harbor, Maine: Jackson Laboratory. Retrieved 29 July 2010.
  14. ^ Connor, A..B. (2006). “Aurora’s Guide to Mo use Colony Management” (PDF)Cell Migration Gateway. CMC Activity Center. Retrieved 19 December 2013.
  15. ^ Garner, J.P.; Weisker, S.M.; Dufour, B.; Mench, J.A. (2004). “Barbering (fur and whisker trimming) by laboratory mice as a model of human trichotillomania and obsessive-compulsive spectrum disorders” (PDF)Comparative Medicine54 (2): 216–24. PMID 15134369. Archived from the original (PDF) on 2013-12-03.
  16. ^ Sarna JR, Dyck RH, Whishaw IQ (February 2000). “The Dalila effect: C57BL6 mice barber whiskers by plucking”. Behavioural Brain Research108 (1): 39–45. CiteSeerX 10680755.
  17. ^ Mogil JS, Wilson SG, Bon K, et al. (March 1999). “Heritability of nociception I: responses of 11 inbred mouse strains on 12 measures of nociception”. Pain80 (1–2): 67–82. doi:10.1016/s0304-3959(98)00197-3PMID 10204719.
  18. Jump up to:a b “BALB/c”Inbred Strains of Mice. Jackson Laboratory. Retrieved 2007-04-16.
  19. ^ “BALB/cByJ”Jax Mice Data Sheet. Jackson Laboratory. Archived from the originalon November 16, 2006. Retrieved 2007-04-16.
  20. ^ “BALB/cJ”Jax Mice Data Sheet. Jackson Laboratory. Archived from the original on 11 April 2007. Retrieved 2007-04-16.
  21. ^ Southwick, C. H.; Clark, L. H. (1966). “Aggressive behaviour and exploratory activity in fourteen mouse strains”. Am. Zool6: 559.
  22. ^ Hilgers, J.; van Nie, R.; Ivanyi, D.; Hilkens, J.; Michalides, R.; de Moes, J.; Poort-Keesom, R.; Kroezen, V.; von Deimling, O.; Kominami, R.; Holmes, R. (1985). Genetic differences in BALB/c sublinesCurr. Top. Microbiol. Immunol. Current Topics in Microbiology and Immunology. 122. pp. 19–30. doi:10.1007/978-3-642-70740-7_3ISBN 978-3-642-70742-1PMID 2994956.
  23. ^ Eicher, E. M.; Beamer, W. G.; Washburn, L. L.; Whitten, W. K. (1980). “A cytogenetic investigation of inherited true hermaphroditism in BALB/cWt mice”. Cytogenet. Cell Genet28 (1–2): 104–115. doi:10.1159/000131518PMID 7470243.
  24. ^ West, Rebecca S.; Hurst, Jane L. (October 2010). “Taming anxiety in laboratory mice”. Nature Methods7 (10): 825–826. doi:10.1038/nmeth.1500ISSN 1548-7105PMID 20835246.
  25. ^ Hurst, Jane L.; Gouveia, Kelly (2017-03-21). “Optimising reliability of mouse performance in behavioural testing: the major role of non-aversive handling”Scientific Reports7: 44999. Bibcode:2017NatSR…744999Gdoi:10.1038/srep44999ISSN 2045-2322PMC 5359560PMID 28322308.
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  27. Jump up to:a b c d “Guidelines for Selecting Route and Needle Size”. Duke University and Medical Center – Animal Care & Use Program. Archived from the original on 9 June 2010. Retrieved 8 April 2011.
  28. ^ A Compendium of Drugs Used for Laboratory Animal Anesthesia, Analgesia, Tranquilization and Restraint Archived 2011-06-06 at the Wayback Machine at Drexel University College of Medicine. Retrieved April 2011
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  30. ^ “Euthanasia”Basic Biomethodology for Laboratory Mice. Retrieved 2012-10-17.
  31. ^ 2013 AVMA Guidelines for the Euthanasia of Animals
  32. ^ Ng, TFF; Kondov, NO; Hayashimoto, N; Uchida, R; Cha, Y; et al. (2013). “Identification of an astrovirus commonly infecting laboratory mice in the US and Japan”PLOS ONE8(6): e66937. Bibcode:2013PLoSO…866937Ndoi:10.1371/journal.pone.0066937PMC 3692532PMID 23825590.
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Further reading[edit]

  • Musser, G.G.; Carleton, M.D. (2005). “Superfamily Muroidea”. In Wilson, D.E.; Reeder, D.M. (eds.). Mammal Species of the World: a taxonomic and geographic reference (3rd ed.). Baltimore: Johns Hopkins University Press. pp. 894–1531. ISBN 978-0-8018-8221-0.
  • Nyby J. (2001). “Ch. 1 Auditory communication in adults”. In Willott, James F. (ed.). Handbook of Mouse Auditory Research: From Behavior to Molecular Biology. Boca Raton: CRC Press. pp. 3–18.

External links[edit]




Further reading



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