Genetically modified mammals are

mammal Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur or ...

s that have been genetically engineered. They are an important category of

genetically modified organism A genetically modified organism (GMO) is any organism whose genetic material has been altered using genetic engineering techniques. The exact definition of a genetically modified organism and what constitutes genetic engineering varies, with ...

s. The majority of research involving genetically modified mammals involves mice with attempts to produce knockout animals in other mammalian species limited by the inability to derive and stably culture embryonic stem cells.

Usage

The majority of genetically modified mammals are used in research to investigate changes in phenotype when specific genes are altered. This can be used to discover the function of an unknown gene, any genetic interactions that occur or where the gene is expressed. Genetic modification can also produce mammals that are susceptible to certain compounds or stresses for testing in biomedical research. Some genetically modified mammals are used as

models A model is an informative representation of an object, person or system. The term originally denoted the plans of a building in late 16th-century English, and derived via French and Italian ultimately from Latin ''modulus'', a measure. Models c ...

of human diseases and potential treatments and cures can first be tested on them. Other mammals have been engineered with the aim of potentially increasing their use to medicine and industry. These possibilities include pigs expressing human antigens aiming to increasing the success of xenotransplantation to lactating mammals expressing useful proteins in their milk.

Mice

Genetically modified mice are often used to study cellular and tissue-specific responses to disease (cf knockout mouse). This is possible since mice can be created with the same mutations that occur in human genetic disorders, the production of the human disease in these mice then allows treatments to be tested. The oncomouse is a type of laboratory mouse that has been genetically modified developed by Philip Leder and Timothy A. Stewart of Harvard University to carry a specific gene called an activated oncogene. Metabolic supermice are the creation of a team of

American American(s) may refer to: * American, something of, from, or related to the United States of America, commonly known as the "United States" or "America" ** Americans, citizens and nationals of the United States of America ** American ancestry, pe ...

scientists led by Richard Hanson, professor of biochemistry at

Case Western Reserve University Case Western Reserve University (CWRU) is a private research university in Cleveland, Ohio. Case Western Reserve was established in 1967, when Western Reserve University, founded in 1826 and named for its location in the Connecticut Western Reser ...

Cleveland, Ohio Cleveland ( ), officially the City of Cleveland, is a city in the U.S. state of Ohio and the county seat of Cuyahoga County. Located in the northeastern part of the state, it is situated along the southern shore of Lake Erie, across the U.S. ...

. The aim of the research was to gain a greater understanding of the

PEPCK-C enzyme Phosphoenolpyruvate carboxykinase (, PEPCK) is an enzyme in the lyase family used in the metabolic pathway of gluconeogenesis. It converts oxaloacetate into phosphoenolpyruvate and carbon dioxide. It is found in two forms, cytosolic and m ...

, which is present mainly in the liver and kidneys.

Rats

A knockout rat is a rat with a single gene disruption used for academic and pharmaceutical research.

Goats

BioSteel is a trademark name for a high-strength based fiber material made of the recombinant spider silk-like protein extracted from the milk of

transgenic A transgene is a gene that has been transferred naturally, or by any of a number of genetic engineering techniques, from one organism to another. The introduction of a transgene, in a process known as transgenesis, has the potential to change the ...

goats, made by Nexia Biotechnologies. Prior to its bankruptcy, the company successfully generated distinct lines of goats that produced recombinant versions of either the MaSpI or MaSpII dragline silk proteins, respectively, in their milk.

Pigs

The

enviropig Genetically modified animals are animals that have been genetically modified for a variety of purposes including producing drugs, enhancing yields, increasing resistance to disease, etc. The vast majority of genetically modified animals are at the ...

is the trademark for a genetically modified line of Yorkshire pigs with the capability to digest plant phosphorus more efficiently than ordinary unmodified pigs that was developed at the University of Guelph. Enviropigs produce the enzyme phytase in the salivary glands that is secreted in the saliva. In 2006 the scientists from National Taiwan University's Department of Animal Science and Technology managed to breed three green-glowing pigs using

green fluorescent protein The green fluorescent protein (GFP) is a protein that exhibits bright green fluorescence when exposed to light in the blue to ultraviolet range. The label ''GFP'' traditionally refers to the protein first isolated from the jellyfish ''Aequorea ...

. Fluorescent pigs can be used to study human organ transplants,Staff (8 January 2008
Fluorescent Chinese pig passes on trait to offspring
AFP, Retrieved 31 August 2012 regenerating ocular

photoreceptor cell A photoreceptor cell is a specialized type of neuroepithelial cell found in the retina that is capable of visual phototransduction. The great biological importance of photoreceptors is that they convert light (visible electromagnetic radiatio ...

s, neuronal cells in the brain, regenerative medicine via

stem cell In multicellular organisms, stem cells are undifferentiated or partially differentiated cells that can differentiate into various types of cells and proliferate indefinitely to produce more of the same stem cell. They are the earliest type o ...

s, tissue engineering, and other diseases. In 2015, researchers at the Beijing Genomics Institute used

transcription activator-like effector nuclease Transcription activator-like effector nucleases (TALEN) are restriction enzymes that can be engineered to cut specific sequences of DNA. They are made by fusing a TAL effector DNA-binding domain to a DNA cleavage domain (a nuclease which cuts DNA ...

s to create a miniature version of the Bama breed of pigs, and offered them for sale to consumers. In 2017 scientists at the Roslin Institute of the University of Edinburgh, in collaboration with Genus, reported they had bred pigs with a modified CD163 gene. These pigs were completely resistant to

Porcine Reproductive and Respiratory Syndrome ''Betaarterivirus suid 1'', formerly ''Porcine reproductive and respiratory syndrome virus'' (PRRSV), is a virus that causes a disease of pigs, called porcine reproductive and respiratory syndrome (PRRS), also known as blue-ear pig disease (in C ...

, a disease that causes major losses in the world-wide pig industry.

Cattle

In 1991, Herman the Bull was the first genetically modified or transgenic bovine in the world.Naturalis (2008). Herman the Bull stabled in Naturalis. Accessed on 3 January 2009 from www.naturalis.nl/naturalis.en/naturalis.en/i000968.html. The announcement of Herman's creation generated considerable controversy.Expatica News (2 April 2004). Herman the bull heads to greener pastures. Accessed on 3 January 2009 from http://www.expatica.com/nl/news/local_news/herman-the-bull-heads-to-greener-pastures--6273.html In 2016 Jayne Raper and her team announced the first trypanotolerant transgenic cow in the world. This team, spanning the

International Livestock Research Institute The International Livestock Research Institute or ILRI is an international agricultural research institute within the CGIAR – formerly the Consultative Group for International Agricultural Research. It was established in 1994 by merger of t ...

, Scotland's Rural College, the Roslin Institute's Centre for Tropical Livestock Genetics and Health, and the

City University of New York The City University of New York ( CUNY; , ) is the Public university, public university system of Education in New York City, New York City. It is the largest urban university system in the United States, comprising 25 campuses: eleven Upper divis ...

, announced that a Kenyan Boran bull had been born and had already successfully had two children. Tumaini – named for the

Swahili Swahili may refer to: * Swahili language, a Bantu language official in Kenya, Tanzania and Uganda and widely spoken in the African Great Lakes * Swahili people, an ethnic group in East Africa * Swahili culture Swahili culture is the culture of ...

word for "hope" – had been given a trypanolytic factor from a baboon via

CRISPR/Cas9 Cas9 (CRISPR associated protein 9, formerly called Cas5, Csn1, or Csx12) is a 160 kilodalton protein which plays a vital role in the immunological defense of certain bacteria against DNA viruses and plasmids, and is heavily utilized in genetic e ...

. p.276

Dogs

Ruppy Ruppy (short for Ruby Puppy) is the world's first transgenic dog. A cloned beagle, Ruppy and four other beagles produce a fluorescent protein that glows red upon excitation with ultraviolet light. Ruppy was created in 2009 by a group of scienti ...

(short for Ruby Puppy) was in 2009 the world's first genetically modified dog. A cloned beagle, Ruppy and four other beagles produced a fluorescent protein that glowed red upon excitation with ultraviolet light. It was hoped to use this procedure to investigate the effect of the hormone

oestrogen Estrogen or oestrogen is a category of sex hormone responsible for the development and regulation of the female reproductive system and secondary sex characteristics. There are three major endogenous estrogens that have estrogenic hormonal activ ...

on fertility. A team in China reported in 2015 that they had genetically engineered beagles to have twice the normal muscle mass, inserting a natural myostatin gene mutation taken from whippets.

Primates

In 2009 scientists in

Japan Japan ( ja, 日本, or , and formally , ''Nihonkoku'') is an island country in East Asia. It is situated in the northwest Pacific Ocean, and is bordered on the west by the Sea of Japan, while extending from the Sea of Okhotsk in the north ...

announced that they had successfully transferred a gene into a primate species ( marmosets) and produced a stable line of breeding transgenic primates for the first time. It was hoped that this would aid research into human diseases that cannot be studied in mice, for example Huntington's disease,

stroke A stroke is a medical condition in which poor blood flow to the brain causes cell death. There are two main types of stroke: ischemic, due to lack of blood flow, and hemorrhagic, due to bleeding. Both cause parts of the brain to stop functionin ...

Alzheimer's disease Alzheimer's disease (AD) is a neurodegeneration, neurodegenerative disease that usually starts slowly and progressively worsens. It is the cause of 60–70% of cases of dementia. The most common early symptom is difficulty in short-term me ...

and schizophrenia.

Cats

In 2011 a Japanese-American Team created genetically modified green-fluorescent cats in order to study HIV/AIDS and other diseases as

Feline immunodeficiency virus Feline immunodeficiency virus (FIV) is a '' Lentivirus'' that affects cats worldwide, with 2.5% to 4.4% of felines being infected. FIV was first isolated in 1986, by Niels C Pedersen and Janet K. Yamamoto at the UC Davis School of Veterina ...

(FIV) is related to HIV.Staff (3 April 2012
Biology of HIV
National Institute of Allergy and Infectious Diseases, Retrieved 31 August 2012

References

{{DEFAULTSORT:Genetically Modified Mammal Genetically modified organisms