In tomorrow’s New York Times, I dig up some of the fossil viruses that have been buried in our genome for tens of millions of years.

This is a subject I’ve explored here on the Loom before (1, 2), but now is a great time to stop and take stock of just how much progress scientists have made in exhuming the ancient invaders that helped make us what we are.

There was one dimension of this research that I didn’t have space to describe, but it’s too cool to let go unmentioned. In the article, I describe a virus protein called syncitin that is essential for placentas to develop. Cells push the protein to their surface, where it lets