SteveGrenard
Philosopher
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http://www.bloomberg.com/apps/news?pid=20601082&sid=apLYpeppu8ag&refer=canada
http://www.timesonline.co.uk/article/0,,2-2513322,00.html
Komodo Dragons, World's Largest Lizards, Have Virgin Births
By Alex Morales
Dec. 20 (Bloomberg) -- Komodo dragons, the world's largest lizards, are capable of virgin births, scientists said after two female specimens laid fertile eggs without mating.
The production of offspring without fertilization by a male, known as parthenogenesis, has been observed before in about 70 vertebrates -- or 0.1 percent of known species -- though never in one as large as a komodo dragon, which can grow up to 3 meters (10 feet) in length and weigh 100 kilograms (220 pounds).
``It's a complete surprise; no one had suspected it before,'' Richard Gibson, one of the paper's co-authors, said in a telephone interview from London Zoo, where one of the females laid her eggs.
``This has ramifications for the natural history of the species in the wild, and its capacity to perpetuate.''
Virgin births have been recorded previously in species of fish, reptiles and amphibians, as well as a turkey, though recorded instances are usually one-offs, according to Gibson.
The discovery of parthenogenesis in two Komodo dragons suggests the phenomenon is more common, he said.
"Not only is it happening in a rare and new species that's also the world's largest lizard, it's happening in two separate, unrelated individuals in different zoos,'' Gibson, curator of amphibians and reptiles at the Zoological Society of London, said. ``That suggests parthenogenesis isn't so rare or unusual as we all thought.''
`Immaculate Conception'
A komodo called Flora in May laid 25 eggs at Chester Zoo, northern England, according to the paper. She had been bred in captivity, and never kept with a male. Eleven of the eggs were viable, and three of those collapsed during incubation, providing material for genetic testing, which also confirmed they were the product of a sole parent, according to the paper. The remaining eggs are due to hatch next month.
"Essentially what we have here is an immaculate conception,'' Kevin Buley, a curator at Chester Zoo and co-author of the paper, said in a statement on Nature's Web site.
A final discovery made by the scientists was that once females have reproduced asexually, they are able to switch back to normal sexual reproduction with males. After her parthenogenetic eggs, Sungai mated with London Zoo's male, Raja, producing a batch of normal eggs before she died in March.
``Inbreeding carries an associated risk of reduced fitness and an increased probability of extinction,'' the paper said. Still, ``parthenogenesis in wild komodo dragons could be adaptive, given that viable offspring are always male and that sexual reproduction can resume, albeit between related individuals, in a colony founded by a single unfertilized female.''
December 21, 2006
Wise men testify to dragon's virgin birth
MARK HENDERSON, SCIENCE EDITOR·
Female Komodo doesn't need a mate · Scientists say it is truly immaculate
A clutch of four Komodo dragons that hatched at London Zoo this year were all the result of virgin births, according to research that could help scientific efforts to protect the world’s largest lizards. Genetic tests conducted at the University of Liverpool have proved that all four born to a female called Sungai were conceived by parthenogenesis, a form of asexual reproduction that is known to take place in lizards but never documented in this species before.
http://www.timesonline.co.uk/article/0,,2-2513322,00.html
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