Female Sharks Can Reproduce Alone, Researchers Find - washingtonpost.com
Female Sharks Can Reproduce Alone, Researchers Find - washingtonpost.com: “Mahmood Shivji — Nova Southeastern’s Guy Harvey Research Institute director and one of the paper’s authors — said that he and his colleagues determined that a byproduct formed when sharks produce eggs, known as a sister polar body, had fused with an unfertilized egg to produce the baby shark, whose DNA had only half as much genetic variability as the mother.
‘Yes, indeed this is a virgin birth,’ Shivji said in an interview, adding that this could help explain why other sharks have suddenly been born in captivity, like a bamboo shark that appeared in Detroit’s Belle Isle Aquarium in 2002.
‘We have now demonstrated that sharks are actually able to use an alternative, previously unknown reproductive pathway, which is parthenogenesis. The problem here is that this alternative reproductive pathway results in offspring that have much lower genetic diversity,’ he said.
The paper’s lead author, Demian Chapman, who did the genetic analysis while pursuing his doctorate at Nova Southeastern and now directs the shark program at the Pew Institute for Ocean Science, said the reduced genetic variability might pose a problem over time if males become scarce under intense fishing pressure and females resort to asexual reproduction. This, in turn, would result in ‘genetically disadvantaged offspring,’ he said.
Still, Chapman added, the virgin birth does serve as a testament to sharks’ resourcefulness. Mammals cannot reproduce asexually.
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