Department of Organismic and Evolutionary Biology, Harvard University, Cambridge MA 02138, USA.
Curr Biol. 2012 Aug 7;22(15):R609-13. doi: 10.1016/j.cub.2012.06.002.
Retroviruses are often expressed in the placenta. Placental expression probably evolved to facilitate retroviral transmission from mother to offspring and from offspring to mother. In the process, the placenta became a site where retroviral genes were 'domesticated' to serve adaptive functions in the host, including the manipulation of maternal physiology for the benefit of the fetus. The evolutionary interplay between retroviruses and host defenses may have contributed to the remarkable diversity of form among mammalian placentas and to mechanisms of genomic imprinting.
逆转录病毒通常在胎盘内表达。胎盘内的表达可能是为了促进逆转录病毒从母亲到后代以及从后代到母亲的传播而进化的。在这个过程中，胎盘成为了逆转录病毒基因被“驯化”以在宿主中发挥适应性功能的场所，包括操纵母体生理学以造福胎儿。逆转录病毒和宿主防御之间的进化相互作用可能促成了哺乳动物胎盘之间形式的显著多样性，并促成了基因组印记的机制。
