A transgenic animal is one whose genome has been altered by the transfer of a gene or genes from another species. In biomedical research, in the laboratory, Transgenic animals are routinely used as models. Over 95 percent of those users are genetically modified rodents, predominantly mice. These mice are important tools for researching on human diseases, and are also used to understand gene function in the context of disease susceptibility, progression and to determine responses to a therapeutic intervention.
Also on the other front due to practical reasons, such as:
The small size of the mice.
Low cost of housing them in comparison to that for larger vertebrates.
Their short generation time.
Their fairly well-defined genetics.
The mice have become the main species used in the field of transgenics. There are mostly three principal methods used for the creation of transgenic animals. Those are DNA microinjection, embryonic stem cell-mediated gene transfer, and retrovirus-mediated gene transfer.
A major advantage of the DNA microinjection method is its applicability to a wide variety of species.
Utilities of Transgenic Animals:
During the medical research, the transgenic animals are mostly used to identify the functions of some specific factors in complex homeostatic systems. These can be through the over- or under-expression of a modified gene (the inserted transgene).
In the toxicology as the responsive test animals for detection of toxicants.
In mammalian developmental genetics.
In the molecular biology, this analysis of the regulation of the gene expression, make use of the informative evaluation of some specific genetic change, at the level of the whole animal.
While in the pharmaceutical industry, for the targeted production of pharmaceutical proteins, and during the drug production also on the product efficacy testing.
In biotechnology, as producers of specific proteins.
For the genetically engineered hormones to increase milk yield, meat production.
In the cloning procedures to reproduce some specific blood lines in the genetic engineering of the livestock, and in the aquaculture that affects the modification of animal physiology and / or anatomy,
Developing animals specially created for use in xenografting.
The benefits of transgenic animals:
Large-scale, low-cost production independent of proximity to the oceans and with reduced environmental impacts.
Increased growth rates.
Improved disease resistance
Improved food-conversion rates
Leaner meat.
Increased muscle mass.
Improved wool quality.
Improved nutritional quality or appeal.
More efficient use of indoor water-recycling plants
Models of human disease processes
As organ transplant donors to humans
Genetic Research
Disadvantages:
While creating the transgenic breeds, there may be a high mortality rate and some other deleterious effects on animals, as observed by the researchers. During the research, it’s been observed that the transgenic pigs that have the enhanced growth rate and efficient feed conversion, exhibit lower reproductive performance. Also these transgenic pigs may suffer from arthritis and dermatitis etc.