Endogenous Viral Element

An endogenous viral element (EVE) is a DNA sequence derived from a virus, and present in the genome a non-viral organism. The crucial step in formation of an EVE is the integration of a DNA sequence derived from a virus into the genome of a germline cell that goes on to produce a viable organism.

By far the most common EVEs in vertebrate genomes are derived from retroviruses. These viruses integrate into the nuclear genome of the host cell as part of their replication cycle, and are thus predisposed to invade the host germline. Furthermore, since integration is a part of the retrovirus replication cycle, endogenous retroviruses (ERVs) may remain capable of producing infectious virus.

In the case of non-retroviral viruses, invasion of the host germ line appears to be a rare, anomalous event, and the resulting EVEs are usually not capable of producing infectious virus, although they may express protein or RNA.