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. [1]
The process of genetically engineering mammals is a slow, tedious, and expensive process. [2] 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 [3] or artificially synthesised . [4] If the chosen gene or the donor organism's genome has been well studied it may already be accessible from a genetic library . The gene is then combined with other genetic elements, includ
A number of techniques are available for inserting the isolated gene into the host genome . With animals DNA is generally inserted into using microinjection , where it can be injected through the cell's nuclear envelope directly into the nucleus , or through the use of viral vectors . [6] The first transgenic animals were produced by injecting viral DNA into embryos and then implanting the embryos in females. [7] It is necessary to ensure that the inserted DNA is present in the embryonic stem cells . [8] Th