It is known that genes inherited from ancient retroviruses are essential to the placenta in mammals,a finding to which scientists in the Laboratoire Physiologie et Pathologie Moleacuteculaires des Retrovirus Endogenes et Infectieux (CNRS/Universite Paris-Sud) contributed. Today, the same scientists reveal a unusual chapter in this account: these genes of viral origin may also be responsible for the more developed muscle mass seen in males. Their findings are published on 2 September 2016 in PLOS Genetics.
Source: phys.org