Virgin Birth: Zebra Shark Has Babies Without Mating

Leonie the zebra shark would not appear to wish a mate: She just lately gave delivery to 3 pups by way of asexual copy on the Reef HQ Aquarium in Townsville, Australia.

Credit score: Tourism & Occasions Queensland

Certain, she used to have a mate on the Reef HQ Aquarium in Townsville, Australia. The pair even had a number of litters earlier than they had been separated in 2012.

However Leonie had been residing aside from males for the previous few years, so her keepers had been stunned when she laid eggs that produced three child sharks in April 2016. Leonie may very well be the primary shark ever noticed to make the change from sexual to asexual copy.

"We thought she may very well be storing sperm; however once we examined the pups and the attainable mother or father sharks utilizing DNA fingerprinting, we discovered they solely had cells from Leonie," stated College of Queensland biologist Christine Dudgeon, who described the case within the journal Scientific Studies Monday (Jan. 16). [7 Unanswered Questions About Sharks]

Leonie's case marks the primary time scientists have seen any such asexual copy —often called parthenogenesis—within the zebra shark (Stegostoma fasciatum).

Cleo and CC, proven right here, are two of the zebra shark pups born and not using a daddy.

Credit score: Tourism & Occasions Queensland

Parthenogenesis happens when embryos develop and mature with out fertilization by a male's sperm. Quite, an egg progenitor cell that normally will get absorbed by the feminine's physique acts as a surrogate sperm to "fertilize" her egg. This copy technique is extra frequent in vegetation and invertebrate organisms. Nonetheless, scientists have been documenting an rising variety of vertebrate species that may have virgin births even when their species usually reproduces sexually. For instance, Komodo dragons, the world's largest lizards, have given delivery by parthenogenesis. So have wild pit vipers, blacktip sharks, chickens and turkeys.

In most of those earlier parthenogenesis instances, the females had been from captive environments and by no means had any publicity to male mates throughout their reproductive prime, Dudgeon and her colleagues wrote. That makes Leonie one of many uncommon people recognized to have had infants by sexual copy solely to modify to asexual copy afterward. (Scientists have reported comparable instances in a boa constrictor and an eagle ray.)

"Leonie tailored to her circumstances, and we consider she switched as a result of she misplaced her mate," Dudgeon stated in an announcement. "What we need to know now's, 'May this happen within the wild?' and, if that's the case, 'How typically does it?' One cause why we've not seen it earlier than may very well be as a result of we've not been in search of it. It is likely to be occurring within the wild, nevertheless it's by no means been recorded on this species earlier than."

If parthenogenesis is certainly an evolutionary adaptation to an absence of appropriate mates, that might have implications for the survival of zebra sharks. The species, which is discovered within the western Pacific and Indian oceans, is listed as endangered on the Worldwide Union for Conservation of Nature's (IUCN) Crimson Listing of Threatened Species.

Dudgeon plans to watch Leonie's pups to seek out out if these asexually produced sharks can have pups of their very own with a male accomplice.

"You lose genetic variety with generations of asexual copy, so we'll be seeing if these offspring can mate sexually themselves," Dudgeon stated.

Authentic article on Stay Science.

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