Genetically modified animals are animals that have been genetically modified for a variety of purposes including producing drugs, enhancing yields, increasing resistance to disease, etc. The vast majority of genetically modified animals are at the research stage while the number close to entering the market remains small.
The process of genetically engineering mammals is a slow, tedious, and expensive process. As with other genetically modified organisms (GMOs), first genetic engineers must isolate the gene they wish to insert into the host organism. This can be taken from a cell containing the gene or artificially synthesised.
If the chosen gene or the donor organism’s genome has been well studied it may already be accessible from a genetic library.