domingo, 12 de agosto de 2012

Snake stores sperm for five years before giving birth

ORIGIN: New Scientist

Virgin Birth or just a really efficient long-term family planning?

Wikimedia Commons
A female rattlesnake, Crotalus adamanteus or commonly known as Eastern Diamondback was collected in Florida in 2005 and kept in a private collection for five years, with no contact with other snakes. In late 2010, she unexpectedly gave birth to 19 snakelets.

Perplexed scientists then took DNA samples of the snake and her triplet to figure out how this happened.

The scientists expected to see an example of a "virgin birth" (parthenogenesis), in which a female produces young without any contribution from a male. But in this case the snakelets carried genes that their mother didn't, so it became clear that she must have mated before she was captured and stored the sperm since more than 5 years.

The female diamond-backed rattlesnake can store sperm for five years (Image: Chris Johns/NGS)
Previous studies have hinted that reptiles can store sperm for several years, but this is the first case confirmed by genetics.

In another instance, a hammerhead female shark was seen giving birth to a shark pup completely via asexual reproduction. Further, this discovery of virgin births in sharks leaves mammals as the only vertebrates not known to be able to reproduce asexually outside of the lab.



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