By Dr Naomi Phillips – Progress.org –
Viral genetic material, integrated into our DNA millions of years ago, has an essential role in a key early stage in embryo
development.
Using a mouse model, scientists in Spain have shown that endogenous retroviruses, part of the genome that was incorporated into DNA following ancient viral infection, influences one of the very first steps in early development. One of these endogenous retroviruses encodes a specific protein
shown to control the switch from totipotency to pluripotency , a step that is required for the mouse embryo to progress past the two-cell stage of development.