biology

People may unsuspectingly choose friends who have some DNA sequences in common with them, a new analysis finds.

Researchers compared gene variations between nearly 2,000 people who were not biologically related, and found that friends had more gene variations in common than strangers.

The study lends a possible scientific backing for the well-worn clichés, "We're just like family," or "Friends are the family you choose," the researchers said.

"Humans are unique in that we create long-term connections with people of our species," said Nicholas Christakis, a social scientist at Yale University involved in the study. "Why do we do that? Why do we make friends? Not only that, we prefer the company of people we resemble."

This does NOT mean that anything ever actually lived there. But it is the first time that the ingredients for the evolution of microbial life, and the correct conditions to support it, have been directly observed beyond Earth. Mars still has water frozen at its poles, and once had quite a bit of water above and below the surface.