The Basic Concept
The term transgenesis most broadly refers to the introduction of genetic material into the germline of a recipient organism; the donated genetic material may come from either the same or different species, or the introduced DNA may be artificial (i.e., generated by DNA synthesis and not present in nature). Technically speaking, the process of carrying out "gene replacement" by homologous recombination can also be considered transgenesis because some introduced foreign DNA is always left at the recombination site. However, for the purpose of clarity, we will refer to homologous recombination as the process of introducing exogenous DNA into a specific site in the genome of a recipient animal (this topic will be discussed later in this chapter) and to transgenesis as the introduction of DNA into a random site. Transgenes can be introduced into mice for a variety of purposes, including to study and define gene promoters, to introduce biomarkers (e.g., green fluorescent protein, b-galactosidase) into specific cell types to distinguish those cells for subsequent in vivo analysis, to selectively "rescue" a gene's function when endogenous copies of that gene have
Was this article helpful?