Animal Biotechnology

TRANSGENIC ANIMALS

• Gordon and Ruddle used the term ‘Transgenic’ for the first time in 1982 to describe genetically modified animals harboring foreign genes within their genome.
• The main objective in the generation of transgenic animals to guarantee that all the somatic cells and germ line cells carry the foreign gene. This necessitates the transfer of foreign genes as early as possible during the development of an animal which means that the foreign genes are introduced into the pronucleus.
• Production of transgenic animals involves a series of steps, starting with cloning of the gene of interest and preparation of DNA samples.
•  In principle, both cloned and chemically synthesized DNA fragments can be used for microinjection.  
• Microinjected embryos are usually transferred to the recipients after a short period of in vitro culture.
• Several methods are available for introduction of DNA into an animal genome. These include
  • DNA- microinjection into pronuclear stage of embryos.
  • Use of retro viruses.
  • Use of embryonic cells.