After Years Alone, Female Shark Reproduces on Her Own

Discovery
After Years Alone, Female Shark Reproduces on Her Own PHOTOGRAPH: DaraKero_F | Zebra shark (DaraKero_F/FLICKR) with CC by (2.0, BY)

A zebra shark in Queensland, Australia has made a remarkable record after giving birth without any partner. Leonie the shark (Stegostoma fasciatum) has transformed from sexual to asexual reproduction, which could help save their species’ dwindling population. She gave birth at Townsville’s Reef Aquarium HQ.

Reports from the Brisbane Times showed that Leonie got separated from her mating partner at the aquarium for nine years now. Leo, her former partner, was moved to a separate aquarium in 2013 due to space constraint. But University of Queensland’s Dr Christine Dudgeon suspected that Leonie had stored Leo’s sperm.

Sexual to Asexual Reproduction

Storing of a male’s sperm is a common trait among several species of sharks. But a DNA analysis ran on Leonie’s offspring revealed that they only carry her DNA. This led Dudgeon to suggest that Leonie developed a specialized mechanism not previously known in the science world.

Dudgeon documented his observation and published the results in the journal Nature. She told the Brisbane Times that their examination with Leonie’s pups would always lead to asexual reproduction. Asexual is common among several species of plants, but it is a rare modality among animals, especially mammals.

No Known Explanation…Yet

“This has been documented from this species before, from an animal in an aquarium in Dubai, but…she had been captured from the wild as an asexual animal and placed in an aquarium and started reproducing asexually when she reached maturity,” Dudgeon said.

Although such change is not surprising in nature, what surprises Dudgeon was how quick the change took place. She said one possible factor that may have contributed to the change was the removal of Leo. This, she said, might have pushed Leonie to resort to different methods of procreation just to continue its lineage.

The International Union for the Conservation of Nature and Natural Resources (IUCN) included zebra sharks under its Red List of threatened species. Scientists all over the world are still clueless as to how this phenomenon even occurred. But Dudgeon said the reason could not be as unusual as it appeared now. The problem is how and where to look for the answer.

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