Transgenic animals

Transgenic animals are animals that have been cloned. The medical and biotechnological uses of animal cloning are almost innumerable, as many diseases have been eradicated thanks to the production of these transgenic animals.

Transgenic animals development

Since the discovery of the molecular structure of DNA by Watson and Crick in 1953, molecular biology research has gained momentum. Molecular biology technology combines techniques and expertise from biochemistry, genetics, cell biology, developmental biology, and Microbiology.

since Watson and Crick’s discovery, there have been breakthroughs in:

recombinant DNA (artificially-produced DNA)
genetic cloning
genomic mapping

The underlying principle in the production of transgenic animals is the introduction of a foreign gene or genes into an animal (the inserted genes are called transgenes). The foreign genes “must be transmitted through the germ line, so that every cell, including germ cells, of the animal contain the same modified genetic material.”26 (Germ cells are cells whose function is to transmit genes to an organism’s offspring.)

Gene transfer by microinjection is the predominant method used to produce transgenic farm animals. Since the insertion of DNA results in a random process, transgenic animals are mated to ensure that their offspring acquire the desired transgene. However, the success rate of producing transgenic animals individually by these methods is very low and it may be more efficient to use cloning techniques to increase their numbers. For example, gene transfer studies revealed that only 0.6% of transgenic pigs were born with a desired gene after 7,000 eggs were injected with a specific transgene.

The ability to produce transgenic animals is reliant on a number of components. One of the first things needed to generate transgenic animals is the ability to transfer embryos. The first successful transfer of embryos was achieved by Walter Heape in Angora rabbits in 1891. Another important component is the ability to manipulate the embryo. In vitro manipulation of embryos in mice was first reported in the 1940s using a culture system. What is also vital is the ability to manipulate eggs. This was made possible through the efforts of Ralph Brinster, attached to the University of Pennsylvania, who in 1963 devised a reliable system to culture eggs, and that of Teh Ping Lin, based at the California School of Medicine, who in 1966 outlined a technique to micro-inject fertilised mouse eggs which enabled the accurate insertion of foreign DNA.

The first genetic modification of animals was reported in 1974 by the virologist Rudolph Jaenisch, then at the Salk Institute, and the mouse embryologist Beatrice Mintz at Fox Chase Cancer Center. They demonstrated the feasibility of modifying genes in mice by injecting the SV40 virus into early-stage mouse embryos. The resulting mice carried the modified gene in all their Tissues. In 1976, Jaenisch reported that the Moloney Murine Leukemia Virus could also be passed on to offspring by infecting an embryo. Four years later, in 1980, Jon Gordon and George Scango together with Frank Ruddle, announced the birth of a mouse born with genetic material they had inserted into newly fertilised mouse eggs. By 1981 other scientists had reported the successful implantation of foreign DNA into mice, thereby altering the genetic makeup of the animals. This included Mintz with Tim Stewart and Erwin Wagner at the Fox Chase Cancer Center in Philadelphia; Brinster and Richard Palmiter at the University of Washington, Seattle; and Frank Costantini and Elizabeth Lacy at Oxford University.

Such work laid the basis for the creation of transgenic mice genetically modified to inherit particular forms of cancer. These mice were generated as a laboratory tool to better understand the onset and progression of cancer. The advantage of such mice is that they provide a model which closely mimics the human body. The mice not only provide a means to gain greater insight into cancer but also to test experimental drugs.

Applications of transgenic animals

Transgenic animals are animals (most commonly mice) that have had a foreign gene deliberately inserted into their genome. Such animals are most commonly created by the microinjection of DNA into the pronuclei of a fertilised egg which is subsequently implanted into the oviduct of a pseudopregnant surrogate mother. This results in the recipient animal giving birth to genetically modified offspring. The progeny are then bred with other transgenic offspring to establish a transgenic line. Transgenic animals can also be created by inserting DNA into embryonic stem cells which are then micro-injected into an embryo which has developed for five or six days after fertilisation, or infecting an embryo with viruses that carry a DNA of interest. This final method is commonly used to manipulate a single gene, in most cases this involves removing or ‘knocking out’ a target gene. The end result is what is known as a ‘knockout’ animal.

Since the mid-1980s transgenic mice have become a key model for investigating disease. Mice are the model of choice not only because there is extensive analysis of its completed genome sequence, but its genome is similar to the human. Moreover, physiologic and behavioural tests performed on mice can be extrapolated directly to human disease. Robust and sophisticated techniques are also easily available for the generic manipulation of mouse cells and embryos. Another advantage of mice is the fact that they have a short Reproduction cycle. Other transgenic species, such as pig, sheep and rats are also used, but their use in pharmaceutical research has so far been limited due to technical constraints. Recent technological advances, however, are laying the foundation for wider adoption of the transgenic rat.

Transgenic rodents play a number of critical roles in drug discovery and development. Importantly, they enable scientists to study the function of specific genes at the level of the whole organism which has enhanced the study of physiology and disease biology and facilitated the identification of new drug targets. Due to their similarity in physiology and gene function between humans and rodents, transgenic rodents can be developed to mimic human disease. Indeed, an array of transgenic mice models have been produced for this purpose. Mice are being used as models, for example, to study obesity, heart disease, diabetes, arthritis, substance abuse, anxiety, ageing, Alzheimer’s disease and Parkinson’s disease. They are also used to study different forms of cancer. In addition, transgenic pigs are being investigated as a source of organs for transplants, which if proven clinically safe could overcome some of the severe donor organ shortages. The development of transgenic animals has recently been transformed by the emergence of the new gene editing tool CRISPR which greatly reduced the number of steps involved in the creation of transgenic animals, making the whole process much faster and less costly.,

Transgenic animals are animals that have had genes from another species inserted into their DNA. The first transgenic animal was a mouse created in 1974. Transgenic animals are used in research to study human diseases and to develop new drugs and therapies. They are also used in agriculture to produce food that is resistant to pests and diseases. The use of transgenic animals is controversial, as some people believe that it is unethical to alter the DNA of animals. However, others argue that the benefits of using transgenic animals outweigh the ethical concerns.

History of transgenic animals

The first transgenic animal was created in 1974 by Rudolf Jaenisch and Beatrice Mintz. They inserted a gene from a mouse tumor cell into a fertilized mouse egg. The resulting mouse, called OncoMouse, developed tumors and died prematurely.

In the 1980s, scientists began to create transgenic animals that were more useful for research. For example, they created mice that were resistant to cancer or that produced human proteins in their milk.

In the 1990s, the first transgenic farm animals were created. These animals were designed to be resistant to diseases or to produce meat that was lower in fat or cholesterol.

Methods of creating transgenic animals

There are several methods of creating transgenic animals. One method is to inject DNA into a fertilized egg. The DNA can be from the same species as the animal, or it can be from a different species.

Another method is to use a virus to deliver DNA into an animal’s cells. The virus can be engineered to carry a specific gene of interest.

Once the DNA has been inserted into an animal’s cells, it must integrate into the animal’s DNA. This process is called gene targeting. Gene targeting is a very precise technique that allows scientists to insert genes into specific locations in the animal’s DNA.

Applications of transgenic animals

Transgenic animals are used in a variety of research applications. They are used to study human diseases, to develop new drugs and therapies, and to test the safety of new drugs.

Transgenic animals are also used in agriculture. They are used to produce food that is resistant to pests and diseases, and to produce food that is higher in nutrients.

Ethical concerns about transgenic animals

The use of transgenic animals is controversial. Some people believe that it is unethical to alter the DNA of animals. They argue that transgenic animals may suffer from Health problems, and that they may be less able to survive in the wild.

Others argue that the benefits of using transgenic animals outweigh the ethical concerns. They argue that transgenic animals have helped to develop new drugs and therapies that have saved lives. They also argue that transgenic animals have helped to improve agricultural yields.

The future of transgenic animals

The use of transgenic animals is likely to continue to grow in the future. Transgenic animals are being used to develop new drugs and therapies for a variety of diseases. They are also being used to produce food that is more nutritious and that is resistant to pests and diseases.

As the technology for creating transgenic animals improves, it is likely that we will see even more applications for these animals. Transgenic animals may one day be used to create organs for transplantation, or to produce biofuels.

What is a gene?

A gene is a basic unit of heredity and is made up of DNA. DNA is a molecule that contains the instructions for how an organism grows and develops.

What is Genetic engineering?

Genetic engineering is the process of modifying an organism’s genes. This can be done by adding, removing, or changing genes.

What are transgenic animals?

Transgenic animals are animals that have had their genes modified using genetic engineering.

How are transgenic animals created?

Transgenic animals are created by inserting genes from one organism into the DNA of another organism. This can be done using a variety of methods, including microinjection, electroporation, and viral vectors.

What are some of the benefits of using transgenic animals?

Transgenic animals can be used to study human diseases, develop new drugs and therapies, and produce food and other products.

What are some of the risks of using transgenic animals?

There are a number of risks associated with using transgenic animals, including the potential for the animals to escape and become invasive species, the potential for the animals to spread diseases to humans or other animals, and the potential for the animals to suffer from health problems.

What are the ethical concerns about using transgenic animals?

There are a number of ethical concerns about using transgenic animals, including the potential for the animals to suffer from health problems, the potential for the animals to be used in experiments that could harm them, and the potential for the animals to be used for food or other products that humans consume.

What is the future of transgenic animals?

The future of transgenic animals is uncertain. There is a great deal of potential for the use of transgenic animals to benefit humans, but there are also a number of risks associated with their use. It is important to carefully consider the risks and benefits of using transgenic animals before making any decisions about their use.

Which of the following is not a type of gene therapy?
(A) Somatic gene therapy
(B) Germline gene therapy
(C) Gene editing
(D) Transgenic animals
Which of the following is a potential risk of gene therapy?
(A) The gene may not be expressed properly.
(B) The gene may be inserted into the wrong location in the genome.
(C) The gene may be passed down to future generations.
(D) All of the above.
Which of the following is a potential benefit of gene therapy?
(A) It can be used to treat genetic diseases.
(B) It can be used to improve the human body.
(C) It can be used to create new organisms.
(D) All of the above.
Which of the following is a type of gene editing technique?
(A) CRISPR-Cas9
(B) Zinc finger nucleases
(C) TALENs
(D) All of the above.
Which of the following is a potential risk of gene editing?
(A) The gene may be inserted into the wrong location in the genome.
(B) The gene may be expressed improperly.
(C) The gene may be passed down to future generations.
(D) All of the above.
Which of the following is a potential benefit of gene editing?
(A) It can be used to treat genetic diseases.
(B) It can be used to improve the human body.
(C) It can be used to create new organisms.
(D) All of the above.
Which of the following is a type of transgenic animal?
(A) A mouse that has been genetically modified to produce human insulin.
(B) A cow that has been genetically modified to produce human Growth hormone.
(C) A pig that has been genetically modified to be resistant to porcine reproductive and respiratory syndrome virus (PRRSv).
(D) All of the above.
Which of the following is a potential risk of using transgenic animals?
(A) The transgene may be expressed improperly.
(B) The transgene may be passed down to future generations.
(C) The transgene may interact with other genes in the animal’s genome in unexpected ways.
(D) All of the above.
Which of the following is a potential benefit of using transgenic animals?
(A) Transgenic animals can be used to produce valuable proteins, such as human insulin and human growth hormone.
(B) Transgenic animals can be used to study the effects of genes on health and disease.
(C) Transgenic animals can be used to test the safety of new drugs and therapies.
(D) All of the above.
Which of the following is a type of cloning technique?
(A) Somatic cell nuclear transfer (SCNT)
(B) Reproductive cloning
(C) Therapeutic cloning
(D) All of the above.
Which of the following is a potential risk of cloning?
(A) The cloned organism may not be healthy.
(B) The cloned organism may have genetic defects.
(C) The cloned organism may not be able to reproduce.
(D) All of the above.
Which of the following is a potential benefit of cloning?
(A) Cloning can be used to produce animals that are identical to a desired animal.
(B) Cloning can be used to produce animals that are resistant to disease.
(C) Cloning can be used to produce animals that are suitable for organ transplantation.
(D) All of the above.