Endogenous retroviruses (ERVs) account for a substantial portion of the genetic pool of
every animal species (eg∼ 8% of the human genome). Despite their overwhelming
abundance in nature, many questions on the basic biology of ERVs are unanswered. The
most important question derives from the observations in many animal species, including
humans, of abundant ERVs expressed in the female genital tract. Sheep harbor
approximately 20 copies of endogenous betaretroviruses (enJSRVs), which are related to�…