Biological shocker: snake reproduces asexually

Jeremy Hance
mongabay.com
November 03, 2010



Researchers have discovered a biological shocker: female boa constrictors are capable of giving birth asexually. But the surprise doesn't end there. The study in Biology Letters found that boa babies produced through this asexual reproduction—also known as parthenogenesis—sport a chromosomal oddity that researchers thought was impossible in reptiles.

While researchers admit that the female in the study may have been a genetic freak, they say the findings should press researchers to re-think reptile reproduction. Virgin birth among reptiles, especially primitive ones like boas, they argue may be far more common than expected.

"Reproducing both ways could be an evolutionary 'get-out-of-jail-free card' for snakes," says lead author Warren Booth, a North Carolina State University postdoctoral entomologist. "If suitable males are absent, why waste those expensive eggs when you have the potential to put out some half-clones of yourself? Then, when a suitable mate is available, revert back to sexual reproduction."


Two offspring from one mom: on the left is the 'normal' offspring produced by mating, on the right is the offspring produced asexually and sporting its mother's unique coloring. Photo by: Sharon Moore.


The mother in question gave birth to not one, but two snake litters of all-female snakes with WW-chromosomes. Male snake cells have two Z chromosomes, while female snakes have a Z and a W. This is the first time a reptile has been seen with two W chromosomes, something thought peculiar to fish and amphibians. The snakes' litters also retained the mother's rare genetic coloring.

The asexual reproduction also wasn't due to a lack of options. Male boas were available to the boa mother and she had previously given birth to other snake litters by mating with males.

The news of the "virgin birth" comes almost four years after a Komodo dragon made headlines for a similar event. Flora, a female Komodo dragon, reproduced asexually at Chester Zoo in Britain in December 2006. The birth was documented in the journal Nature.

Parthenogenesis is so far known to occur in about 70 reptile species.





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CITATION:
Jeremy Hance
mongabay.com (November 03, 2010).

Biological shocker: snake reproduces asexually .

http://news.mongabay.com/2010/1103-hance_asexualboa.html