Fatherless Shark Pups Can Survive Over Long Term
January 25, 2010
By Juliet Eilperin
Shark offspring born to virgin mothers can survive over the long term, according to a new study published Monday.
The paper, published in the Jan. 25 edition of the Journal of Heredity, shows the pups of female sharks that have not been impregnated by a male -- a process known as parthenogenesis -- can live for an extended period of time.
Kevin Feldheim, manager of the Pritzker Laboratory for Molecular Systematics and Evolution at the Field Museum, collaborated with colleagues in examining two daughters of a white-spotted bamboo shark that are now more than five years old.
Earlier research had proved that two other shark species had reproduced without receiving male sperm, but those babies did not survive.
"These findings are remarkable because they tell us that some female sharks can produce litters of offspring without ever having mated with a male," Feldheim said. "Examination of highly variable sections of the genome prove that these young sharks had no father."
Demian Chapman of the Institute for Ocean Conservation Science at Stony Brook University, who co-wrote the current study and pioneered the work proving virgin shark births can happen, said the new findings demonstrate "parthenogenesis may not be as much of a dead-end mode of reproduction as we thought for these sharks," even though these offspring lack the same genetic diversity as pups produced through intercourse.
The mother of the two virgin sharks in question was kept in a tank at the Belle Isle Aquarium in Detroit, where only another female of a different but related species resided. The new genetic testing rules out the possibility that the female shark could have come into contact with male sperm earlier in her life.
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