Advantages Of Transgenesis

Transgenesis is a procedure in which a gene or part of a gene from one individual is incorporated in the genome of another one. Transgenic animals have any of these genetic modifications with potential use in studying mechanisms of gene function, changing attributes of the animal in order to synthesize proteins of high value, create models for human disease or to improve productivity or disease resistance in animals.

The objectives for animal biotechnology in food production and medicine are animal growth rate and meat production, milk yield and milk quality, wool production and quality, resistance to disease, digestion of normally non-digestible feeds or nutrients, producers of human pharmaceutical and transgenic animals, mostly pig will be

Human milk lacks β-lactoglobulin which is a main allergenic milk component, but has a higher content in lactoferrin and lysozyme when compared to ruminant milk. To introduce the human lactoferrin into the bovine milk, transgenic cows have been obtained. The objective is to eliminate β-lactoglobulin because it is one of the major allergens of cow 's milk.

Transgenesis was also done to reduce the content of lactose in the milk to allow their consumption to people with intolerance to lactose. 70% of the world population lacking the intestinal lactase, the enzyme required to digest the lactose. The reduction in lactose may be obtained by expressing β-galactosidase in the milk or diminishing the content of α-lactalbumin. However, the limitation of this method is that this milk is very viscous and it is not secreted to the exterior of the mammary gland, due to the importance of the lactose in the osmoregulation of the

The objective is to alter the concentrations of antibacterial proteins such as lysozyme or transferrin in the milk.

Transgenesis was also done for meat production. The pioneering experiment of Palmiter and co-workers, made in 1983 produced giant mice. The mice were obtained by over-expressing the rat growth hormone’s gene fused to mouse methionine promoter. Since that, many experiments have been made to increase growth rate of farm animals in order to increase meat production and to lower its cost.

Besides that, animal transgenesis was done for disease resistance. Few examples of transgenic animals are transgenic chicken and mice. Transgenic chickens with defective avian leucosis virus (ALV) were protected against retroviral infections and less susceptible to tumors compared to normal chickens (SALTER & CRITTENDEN, 1989). Transgenic mice with a gene coding for g-interferon showing increased resistance to pseudo rabies virus (CIONI ET AL.,