We have completed maintenance on DiscoverMagazine.com and action may be required on your account. Learn More

Against All Odds, Sex Has Returned

A mite reevolves sex after hundreds of millions of years without it.

By Robert Liota
Jun 19, 2007 5:00 AMNov 12, 2019 5:13 AM

Newsletter

Sign up for our email newsletter for the latest science news
 

Richard Dawkins said it was statistically improbable; Louis Dollo, a French paleontologist, famously developed a hypothesis stating that it could never happen. But a tiny soil mite smaller than a pinhead has reevolved the ability to mate, according to a study by evolutionary geneticists Katja Domes of the Technical University of Darmstadt, Germany, and Roy Norton of the SUNY College of Environmental Science and Forestry in Syracuse.

After analyzing various mites’ DNA, the duo concluded that the sexually reproducing Crotoniidae mite is a descendant of Camisiidae mites, which have reproduced asexually for hundreds of millions of years since they themselves evolved from a sexually reproducing ancestor. Through a process called parthenogenesis, Camisiidae females typically lay eggs that are exact copies of themselves. Although males are born every once in a while, they are always sterile. Or so it was thought.

“Those rare males may have enabled Crotoniidae to reevolve sex,” says Domes. Usually when traits fall into disuse, their corresponding genes quickly mutate to code for something else. So when something as complex as the ability to produce sex gametes is lost, it’s likely never to be developed again. Oddly, the Camisiidae mites seem to have retained that ability, despite surviving millions of years without using it.

1 free article left
Want More? Get unlimited access for as low as $1.99/month

Already a subscriber?

Register or Log In

1 free articleSubscribe
Discover Magazine Logo
Want more?

Keep reading for as low as $1.99!

Subscribe

Already a subscriber?

Register or Log In

More From Discover
Recommendations From Our Store
Shop Now
Stay Curious
Join
Our List

Sign up for our weekly science updates.

 
Subscribe
To The Magazine

Save up to 40% off the cover price when you subscribe to Discover magazine.

Copyright © 2024 Kalmbach Media Co.