Scientists have revealed that a female shark which was separated from her mate managed to have babies on her own. A female specimen of the species known as Stegostoma or the zebra shark met her partner back in 1999 at an aquarium in Townsville, Australia. Before the male shark was moved into another tank in 2012, they had together approximately 24 offsprings.
From that moment on, Leonie, the female shark did not have contact with another male. Nevertheless, despite this situation, the zebra shark managed to three babies on her own. Scientists were triggered by this phenomenon, wanting to know more about the way in which this female shark managed to reproduce.
Christine Dudgeon, a researcher at the University of Queensland in Brisbane Australia together with her colleagues, managed to analyze this shark more to establish the method it used to reproduce. One of the ideas assumed by scientists was that this female zebra shark has been storing her ex’s sperm and she might have used it to fertilize her eggs.
Nevertheless, after researchers decided to test Leonie’s babies, they figured out that they carried only their mother’s DNA, revealing that they were conceived by using asexual reproduction. Several species of vertebrates are capable of reproducing asexually even if they usually reproduce sexually. Among these species, scientists have listed rays, snakes, Komodo dragons, turkeys, and sharks.
Nonetheless, the most reports concerned females which had never had a male partner. Dudgeon claimed that there are few reports regarding females which had previously had a partner. A boa constrictor and an eagle ray which were both kept in captivity proved to be the only females until now which managed to turn asexual from sexual.
Russell Bonduriansky, a scientist at the University of New South Wales in Sydney, pointed out that for species which can reproduce by switching between these two modes, some observations need to be mentioned. Nevertheless, scientists claim that is more common to observe a transformation from asexual to sexual mode.
Dudgeon has explained that asexual reproduction happens when the egg of a female is fertilized by an adjacent cell called a polar body. This cell contains the genetic material of the female, causing “extreme inbreeding.”
Image source: wikipedia