Dr. Ian Malcolm said it over 20 years ago in Jurassic Park, and now real-life scientists are repeating his wise words: Life finds a way. A new study has announced that an endangered relative of the shark, the smalltooth sawfish, has figured out how to save its species by reproducing without sex. The fish has managed a form of asexual reproduction, or virgin births.
This curious miracle of nature was discovered a couple years ago by researchers doing genetic analysis to see if sawfish were inbreeding, Nature reported. Instead, they found the first signs something more unusual had happened.
What the curious creature — which can grow to about 25 feet long — had figured out is called parthenogenesis, just a fancy word for virgin births. In this phenomenon, a female animal fertilizes her own egg. This is accomplished when her unfertilized egg “absorbs a genetically identical sister cell,” Discovery explained. The pups aren’t clones, but they only get their genes from her.
The reason they are resorting to virgin births may be a warning sign, however. It indicates that the female can’t find a mate, and that’s because the species is nearing extinction. It may be the first family of marine life to do so.
Researchers only have theories as to the motivation, said the study’s author and fish geneticist Andrew Fields.
“Is this a special case because we have an endangered species with very few individuals and they don’t run into each other, or is it because they’re sawfish and sawfish have something interesting going on?”
The fish is one of five types of ray, related to the shark, and used to be quite plentiful near the coasts from North Carolina to Texas. Humans made sure they didn’t stick around for long — we fished them so much, the population is now five percent of what it was when Europeans first came to our shores. These days, they only live in the waters off Florida.
No wonder it’s turned to virgin births. However, this isn’t exactly an ideal way to go about repopulating your species. Parthenogenesis creates a homogeneous gene pool, and that lack of diversity means the animals are more prone to mutation or vulnerable to changes in their environment. Most of the time, the offspring resulting from virgin births die.
But the sawfish are a bit different. The seven studied appeared to be quite normal and they were born and have thrived in the wild — they were actually born in 2011. The question now is whether they can reproduce, either without a partner or with one. It’ll be awhile before they know — the fish don’t reach sexual maturity for seven years. This phenomenon is also incredible because while virgin births have happened before, they’ve always occurred in captivity, LiveScience added. The Komodo dragon has managed to do so, as have chickens, turkeys, snakes, and the shark.
This is the first time, therefore, a vertebrate animal — it has a skeleton of cartilage like a shark — has managed parthenogenesis in nature. But sadly, it likely won’t save it from extinction.
“Rare species, like those that are endangered or colonizing a new habitat, may be the ones that are doing it most often. Life finds a way,” said the study’s co-author Demian Chapman.
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