Lone Zebra Shark Surprises Aquarium With Rare "Virgin Birth"

[Garrison Hilliard]

(Video at site)

A female zebra shark named Leonie in Australia has shocked scientists by
producing three offspring after spending years away from her male partner.
Subsequent analysis found that she had simply developed the ability to do
it all on her own..
Researchers with Australia’s University of Queensland (UQ) observed the
change at the Reef HQ Aquarium and have documented it in a new study in
the journal Scientific Reports.
Leonie was first paired with a male zebra shark at an Australian aquarium
in 1999, at which time the couple had over two dozen babies. In 2012,
aquarium staff moved Leonie’s partner to another tank, leaving her all by
herself — which is why scientists were stunned when she gave birth last
year.
Was it immaculate conception? Asexual reproduction? Evolution finally
doing right by women?
University of Queensland researcher Christine Dudgeon and her colleagues
have floated some theories.
At first, it seemed Leonie might have been saving sperm from her last male
partner to use later on to help her conceive. But after genetic testing,
researchers found that Leonie’s babies only had their mother’s DNA.
“It might be a holding-on mechanism,” Dudgeon told New Scientist. “Mum’s
genes get passed down from female to female until there are males
available to mate with.”
In other words, it could be a kind of biological contingency plan for if
there are no male sharks around. It’s not too far-fetched: According to
New Scientist, sharks are capable of asexual reproduction if there’s a
genetically identical cell called a sister polar body nearby to fertilize
it.
Unfortuntely, Dudgeon said female asexual reproduction isn’t sustainable
for sharks over time because it results in “extreme inbreeding,” taking a
toll on genetic diversity and adaptability — crucial components for the
survival of any species.
But the phenomenon of animals going from being sexual to asexual creatures
(rather than the reverse, which often occurs in species capable of both
reproductive processes) may be more common than scientists currently
realize. Dudgeon said it’s something that requires more investigation.
University of Queensland associate professor Russell Bonduriansky said
researchers came to at least one conclusion regarding Leonie’s
reproductive loophole.
He told New Scientist, “It would seem to be highly advantageous.”

http://canadajournal.net/science/lone-zebra-shark-surprises-researchers-pups-54913-2017/