Pit vipers capable of virgin birth: Scientists
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Last Updated: Wednesday, October 19, 2011, 18:10
  
Washington: For the first time, scientists have discovered that deadly pit vipers are capable of virgin birth, or have the ability to reproduce without sex like their constrictor relatives.

Researchers at the North Carolina State University in theUS have also found that female pit vipers can conserve sperm after sex for at least five years, shedding light on the lengths these serpents can go to in order to procreate.

A sexual reproduction is common among invertebrates -- or the animals without backbones -- and is rare in vertebrates, although it's not unheard of.

Scientists have already found that komodo dragon, world's largest living lizard, giving birth via parthenogenesis, in which an unfertilised egg develops to maturity. Such virgin births have also been seen in sharks, birds and amphibians. A boa constrictor has also been found having this ability.

But, this is for the first time, the researchers found that pit vipers can do so as well, LiveScience reported.

For their research, evolutionary geneticist Warren Booth of North Carolina State University and his colleague Gordon Schuett looked at a female copperhead (Agkistrodon contortrix) kept at the North Carolina Aquarium at Fort Fisher.

Over the past five years, she had come into contact with only one corn snake (Pantherophis guttatus) and interbreeding between the two species is considered unlikely or impossible.

In 2009, this copperhead gave birth to a litter of four offspring that were outwardly normal in appearance, two of which were alive at birth.

Analysis of DNA from the mother, one live offspring and one of the stillborn progeny revealed no signs of genes from a father, suggesting a true virgin birth, the researches said.

"With the availability of DNA fingerprinting techniques,we are now becoming aware that the process of parthenogenesis is in fact more common than we ever imagined," Booth said.

According to the researchers, who detailed their findings in the Biological Journal of the Linnean Society, these snakes may have evolved parthenogenesis as a mechanism to fight a lack of suitable mates.

"Instead of wasting eggs, which are costly to produce and a finite resource, parthenogenesis may represent an alternate means of reproduction to overcome this," Booth said.

In light of the loss of habitat these snakes face, virgin births might allow this species to hold on a little longer, he added.

The scientists also looked at a eastern diamond-backed rattlesnake, which was captured while sexually immature and kept isolated from males in captivity for at least five years. In 2010, it gave birth to 19 healthy offspring and DNA analysis of the mother and the offspring revealed genes from a father in each of the progeny.

This suggests that the single mother had mated with one or more males before her capture and conserved the sperm for at least five years until she was mature enough to reproduce.

"Mating opportunities may be rare in many species," Booth said. It therefore makes sense for them to have solved the problem "through the evolution of mechanisms by which mating can occur when the opportunity arises and the spermatozoa stored until needed."

Understating the mechanisms behind successful long-term sperm storage may have potential application to both human and livestock sperm storage, Booth added. PTI


First Published: Wednesday, October 19, 2011, 18:10


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