A transgenic animal is that carries a foreign gene inserted into its genome. You can also say that a transgenic animal can be the one which has had its DNA manipulated. This is manipulated to express a foreign gene supplied by another organism. To use in a wide range of applications in medicine, industry and agriculture, many transgenic animal like transgenic rats, rabbits, pigs, sheep, cows and fish have been produced.
Methods of creation of transgenic animals
Now let us see the various methods of creation of transgenic animals:
Creation of transgenic animals involves the direct microinjection. In this method, a gene is chosen from member of the same species or different species and inserted into the fertilized ovum. It was used in mammals and the insertion of DNA is a random process. This manipulated fertilized ovum is then later transferred into the oviduct of a recipient female. The most important advantage of this method is that it is applicable to a wide variety of species.
Another method of creation of transgenic animals involves inserting the desired DNA sequence in a homologous recombination. This is done into in-vitro culture of embryonic stem (ES) cells. An undifferentiated cell which can differentiate any type of cell to complete organism is called Stem cells. These cells with an embryo at the blastocyst stage of development results in chimeric animal. This method is for gene inactivation and called knock-out method. This creation of transgenic animals method is used in the study of the genetic control of developmental processes.
Retroviruses are used as vectors in the creation of transgenic animals to transfer genetic material into the cell. This done using retroviruses, because it can infect host cells. In this method, they produce chimeric. If retrovirus is integrated into germ cells, then transgene can be transmitted.
Medical Applications
In medical science, transgenic animals help in understanding the role genes in development of diseases. They also let you know on how to test the safety and efficiency of new drugs. Now let us discuss a few medical applications of the transgenic animals:
To study how genes are regulated we use transgenic animals. They also help us in knowing how they affect the normal functions of the body and its development. It includes the study of complex factors in the regulation of normal physiology and growth such as insulin-like growth factor (IGF).
Transgenic animals are used to increase the understanding of how genes are used in the contribution of the development of disease. To produce the disease symptoms, these animals are genetically developed. In the present world, transgenic models are used in various diseases like the Alzheimer’s disease, arthritis, cystic fibrosis, rheumatoid and cancer.
In some cases, there are some transgenic animals which are used in producing creating specific products. Due to economic reasons, greater quantities of a product are made at much cheaper cost. One of such an example is that the cows produce milk that has particular human proteins. This can be used to treat emphysema. You can use such things for the treatment of phenylketonuria (PKU) and cystic fibrosis. The first transgenic cow, Rosie was used to produce human protein enriched milk (2.4 grams per litre) in 1997. To the surprise, the so produced milk had the human protein alpha lactalbumin.
As a medicinal application, the transgenic mice can also be used for testing the safety of vaccines. Before applying these vaccines on the human, you can test it on the transgenic animal. Later, they can completely replace the monkeys in testing the safety of polio vaccines.
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