Thaindian News

Washington, Sep 27 (IANS) How mammals reproduce today depends on a more than 100 million years old invasion of the mammalian genome by genetic parasites which radically changed the way mammals produce their young ones, new research suggests.

The parasites known as junk DNA transformed the uterus of human ancestors and other mammals from the production of eggs to a nurturing home for developing young ones, the study has found.

“In the last two decades there have been dramatic changes in our understanding of how evolution works,” said Gunter Wagner, study author and professor of ecology and evolutionary biology at Yale, the journal Nature Genetics reports.

“We used to believe that changes only took place through small mutations in our DNA that accumulated over time. But in this case, we found a huge cut-and-paste operation that altered wide areas of the genome to create large-scale morphological change,” said Wagner.

The Yale team studying the evolutionary history of pregnancy looked at cells found in the uterus associated with placental development, according to a Yale statement.

They found more than 1,500 genes expressed in the uterus of placental mammals, thanks to transposons, selfish pieces of genetic material that replicate within the host genome, and used to be called junk DNA.

“These transposons are more like prefabricated regulatory units that install themselves into a host genome, which then recycles them to carry out entirely new functions like facilitating maternal-foetal communication,” said Vincent J. Lynch, Yale research scientist in ecology who led the study.