Tuesday, March 14, 2006

Facultative Parthenogenesis

Or virgin birth.

Facultative parthenogenesis is the term for what occurs when a species which normally reproduces sexually reproduces asexually. Some snakes, lizards and turkeys do it, according to Toledo (OH) Blade science writer Jenni Laidman. (Link)

The Toledo Zoo reports it has happened there more than once, with snakes. In one case a keeper had a tiny viper "drop in unexpectedly" within an "emptied" exhibit space.

"The fact that these species normally produce sexually is an important distinction, because among reptiles and amphibians, there are the few oddball types that only reproduce asexually. In fact, one of them, a form of blue-spotted salamander, lives in northwest Ohio. This species is all female. She produces eggs with double the genetic material of a normal egg, meaning she need not wait for sperm to provide her offspring with a full complement of genes."

"But facultative parthenogenesis takes place in females not known to play such tricks. And usually, it comes as a surprise.

"Take the story of the Sri Lankan pit viper at the Toledo Zoo. It hadn't seen a male for years. Then one day a keeper moves the pit viper cage only to be pelted by a baby viper falling from atop the mesh cover on the viper tank."

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Anonymous DeLene said...

I think this happens with some shark species too. But my understanding is that it happens only when the animal is under extremely unnatural conditions, like being isolated for very long periods of time in captivity. Do you know if that is true?

8:49 PM  

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