(Telegraph) Female leopard shark makes world-first switch from sexual reproduction to impregnate herself
A female leopard shark has become the first known shark to switch from sexual to asexual reproduction.
This is only the third known instance in all vertebrate species.
Leonie, from an aquarium in Queensland, managed to reproduce asexually after being separated from her mate.
The shark was captured from the wild in 1999 and taken to the Reef HQ aquarium in Townsville, Queensland.
In 2006, she was introduced to a male shark.
Leonie began laying eggs in 2008 and had several litters of sexually produced offspring before being separated from her male in 2012.
Since 2013, she has been sharing a tank with one of her female offspring, Lolly.
In 2014, both the sharks laid eggs, but this was not unusual and they did not contain embryos.
However, the following year, the sharks produced eggs that contained embryos and in the end there were five viable hatchlings.
Leonie’s hatchlings were tested, and they exhibited elevated homozygosity, so were not the result of stored sperm.
This proved they were produced asexually.
Dr Christine Dudgeon, a biologist with the University of Queensland, told The Guardian: “The onset of asexual reproduction with the onset of maturity has been documented before with sharks, and rays, and particularly with reptiles, but what we have shown for the first time is the switch”.