Power of one

Female shark becomes pregnant without male partner in a scientific first

A boy and his mother watch as a diver feeds a Zebra Shark and other tropical fish at the Aquarium of the Pacific in Los Angeles on November 26, 2009. (MARK RALSTON/AFP/Getty Images)

Leonie the zebra shark is a scientific wonder: She became pregnant and gave birth to three healthy shark “pups” without any male contact. While she did give birth after intercourse with a male partner in the early 2000s, the babies she produced are entirely hers, without any male genetic contributions. This type of asexual reproduction (or “parthenogenesis, as scientists call it) has been seen in nature before, but Leonie is the first ever shark to have gone from sexual to asexual reproduction. This shows that Leonie adapted to her circumstances when male partners became scarce, in a switch that is very rarely observed and barely understood by scientists. There are only two other such observed cases: In a female eagle ray and female boa constrictor. Scientists believe this evolutionary strategy has limited advantages though, as it limits genetic variety, making the animal slower to adapt and more vulnerable to unwelcome genetic mutations. Moreover, Leonie’s children will most likely be asexual reproducers themselves, meaning they have limited use in the tiger shark gene pool. “It might be a holding-on mechanism,” study author Christine Dudgeon at the University of Queensland in Brisbane, Australia told New Scientist. “Mum’s genes get passed down from female to female until there are males available to mate with.” Yes, scientists seem to suggest the ability to become pregnant without a male may not be all that advantageous, but just a few days into Trump’s presidency, it’s some nice food for thought.

Read the full story at PopSci.

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