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."
Four hundred and twenty-five million years ago, a strange creature shaped like a Christmas tree roamed the Earth – which makes it surprisingly young.
This 2-centimetre-long fossil arthropod, named Enalikter aphson, was found in rocks in Herefordshire, UK. It is the most recent addition to the megacheira, an extinct group of marine arthropods – and finding it in the 425-million-year-old rocks could indicate that megacheirans were distant ancestors of all arthropods alive today, including lobsters and spiders.