Virgin On The Incredible
Study confirms virgin birth of zoo shark pup
Ian Sample
Wednesday May 23, 2007
The Guardian
A hammerhead shark, a close relative of the bonnethead, a species that a study has found is capable of 'virgin births'. Photograph: John Bazemore/AP
Scientists have solved the mystery of how a baby shark appeared in a tank of females without the help of a male: it was a virgin birth. The bonnethead shark was born through "parthenogenesis", a process where an egg develops into an embryo without being fertilised by sperm.
Virgin births, possible in some birds, amphibians, reptiles and bony fishes, are extremely rare. It had never before been confirmed in cartilaginous fish, such as sharks and rays. The birth, in 2001, astonished scientists as placental animals, including this shark, were thought to need genetic material from sperm and egg to produce viable young.
The genetic tests on the shark - finally published after six years - confirmed this was a virgin birth.
The shark pup was born at the Henry Doorly zoo, Omaha, Nebraska, in a tank holding three female bonnetheads caught as young off Florida, a male leopard shark and a stingray. The females had been separated from males of their own species for more than three years.
The scientists thought one female might have retained sperm after mating with a male in the wild, or reproduced with the leopard shark. But the pup had no male DNA, and was genetically identical to one of the females.
The study, by researchers at the zoo, as well as at Queen's University, Belfast, and the Guy Harvey Research Institute in Florida, appears today in the Royal Society journal Biology Letters.
Ian Sample
Wednesday May 23, 2007
The Guardian
A hammerhead shark, a close relative of the bonnethead, a species that a study has found is capable of 'virgin births'. Photograph: John Bazemore/AP
Scientists have solved the mystery of how a baby shark appeared in a tank of females without the help of a male: it was a virgin birth. The bonnethead shark was born through "parthenogenesis", a process where an egg develops into an embryo without being fertilised by sperm.
Virgin births, possible in some birds, amphibians, reptiles and bony fishes, are extremely rare. It had never before been confirmed in cartilaginous fish, such as sharks and rays. The birth, in 2001, astonished scientists as placental animals, including this shark, were thought to need genetic material from sperm and egg to produce viable young.
The genetic tests on the shark - finally published after six years - confirmed this was a virgin birth.
The shark pup was born at the Henry Doorly zoo, Omaha, Nebraska, in a tank holding three female bonnetheads caught as young off Florida, a male leopard shark and a stingray. The females had been separated from males of their own species for more than three years.
The scientists thought one female might have retained sperm after mating with a male in the wild, or reproduced with the leopard shark. But the pup had no male DNA, and was genetically identical to one of the females.
The study, by researchers at the zoo, as well as at Queen's University, Belfast, and the Guy Harvey Research Institute in Florida, appears today in the Royal Society journal Biology Letters.