Transgenic animals: The melding of molecular biology and animal reproduction

Biotechnology applied to livestock encompasses various reproductive techniques supported by molecular biology. Technologies for the transfer of gene constructs involve microinjection into the pronucleus of fertilized oocytes or DNA mass transfer. The last one can be made through the use of sperm, which carry the incorporated gene construct into the ovum at fertilization, or through the use of retroviral vectors in cell lines. One of the prerequisites to establishing transgenic lines is the presence of the foreign DNA in the gametes or one-cell embryos to ensure that the conceptus develops into a transgenic animal. To reach this objective, foreign genes can be transferred using different methods and strategies depending up on the species of domestic animal used for this venture and their biological potential. Transgenic animals are now commonly used worldwide as models for human disease and the commercial availability of transgenic protein products for therapeutic use is thought to be nearing realization. Advanced research is being conducted in areas such as organ development for human transplantation and improved animal production. Transgenic animals provide a true in vivo environment for evaluating the mechanisms by which gene expression is modulated during development and in adults. “Animal pharming”, the process of using transgenic animals to produce pharmaceutical proteins for human use, is staking its claim in a lucrative world market since the inserted gene, enables an animal to generate the targeted pharmaceutical protein in its milk, urine, blood, sperm, or eggs, or to grow rejectionresistant organs for transplant. This paper is a brief review of the most recent events in the area of domestic animal trangenesis.