Scientists have confirmed a second “virgin birth” in a shark.
In a study reported today in the Journal of Fish Biology, scientists said DNA testing proved a pup carried by a female Atlantic blacktip shark in the Virginia Aquarium & Marine Science Center carried no genetic material from a male.
The first documented case of asexual reproduction, or parthenogenesis, in sharks involved a hammerhead at an Omaha, Neb., zoo.
“This first case was no fluke,” Demian Chapman, a shark scientist and lead author of the second study, said. “It is quite possible that this is something female sharks of many species can do on occasion.”
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The aquarium sharks each carried only one pup, while some shark species can produce litters of a dozen or more. The scientists cautioned that the rare asexual births should not be seen as a possible solution to declining global shark populations.
“It is very unlikely that a small number of female survivors could build their numbers up very quickly by undergoing virgin birth,” Chapman said.
Virgin birth has been proved in some bony fish, amphibians, reptiles and birds, and has been suspected among sharks in the wild. The scientists who studied the Virginia and Nebraska sharks said the pups acquired one set of chromosomes when the mother's chromosomes split during egg development, then united anew.