HARMLESS VIRUSES APPARENTLY STOWED AWAY for millions of years in the DNA of mammals have proved to be more than idle passengers.
New research in live sheep has demonstrated for the first time that they help embryos change shape, implant themselves in the womb and grow a placenta. The same almost certainly happens in other mammals, including humans, they say.
The findings provide new insights into how so-called endogenous retroviruses (ERVs) and mammals evolved together to the mutual advantage of both. ERVs typically account for 8% to 10% of the DNA in most mammals, including humans.
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It will be interesting to see what other ERV’s have had an effect on the fitness of other organisms. This is a fascinating find.