Shark’s virgin birth

Scientists say a female shark gve birth in captivity despite having no contact with a male shark.

It’s led them to conclude that female hammerhead sharks can reproduce without having sex, reports the BBC.

The evidence comes from a shark at Henry Doorly Zoo in Nebraska which gave birth to a pup in 2001 despite having had no contact with a male.

Genetic tests by a team from Belfast, Nebraska and Florida have proved conclusively the pup possessed no paternal DNA, Biology Letters journal reports.

The type of reproduction exhibited – parthenogenesis – had been seen before in bony fish but never in cartilaginous fish such as sharks.

The investigation of the birth was conducted by the research team from Queen’s University Belfast, the Southeastern University in Florida, and Henry Doorly Zoo itself.

The scientists say the discovery raises important issues about shark conservation.

If dwindling shark numbers resort to parthenogenesis to reproduce, this is likely to weaken populations still further, the researchers warn.

The reason is that asexual reproduction reduces genetic diversity and this makes it harder for organisms to adapt – to changed environmental conditions or the emergence of a new disease, for example.

Dr Paulo Prodohl, a co-author of the report, said: “The concern for sharks is that not only could we be reducing their numbers but we could be making them less fit as well.”

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