Invasion of genomic parasites triggered modern mammalian pregnancy

[Tank]

Invasion of genomic parasites triggered modern mammalian pregnancy

Genetic parasites invaded the mammalian genome more than 100 million years ago and dramatically changed the way mammals reproduce -- transforming the uterus in the ancestors of humans and other mammals from the production of eggs to a nurturing home for developing young, a new Yale University study has found.

The findings published online Sept. 25 in the journal Nature Genetics describe in unprecedented detail the molecular changes that allowed mammals to carry their developing young within the safety of the womb rather than laying them in nests or carrying them around in pouches.

"In the last two decades there have been dramatic changes in our understanding of how evolution works," said Gunter Wagner, the Alison Richard Professor of Ecology and Evolutionary Biology (EEB) and senior author of the paper. "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."...

An interesting example of how mutation in DNA leads to morphological changes in an organism.

[Whitney]

parasites that can drastically modify genetics....a scary idea.

[Tank]

parasites that can drastically modify genetics....a scary idea.

It's one of the theories that has been proposed for the evolutionary advantage of sexual reproduction. Sexual reproduction shuffles the genes in each generation which creates more variability and makes it much harder for parasites to zero in on the characteristics of its vector. The sexually reproducing creature out-evolves its parasites.