This Mutant Crayfish Can Clone Itself—And It's Starting to Take Over Entire Countries

Monday, 05 February 2018 - 8:51PM
Monday, 05 February 2018 - 8:51PM
This Mutant Crayfish Can Clone Itself—And It's Starting to Take Over Entire Countries
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U.S. Fish and Wildlife Service/Zachary Loughman, West Liberty University
Most crayfish are typically unremarkable, being as interesting as a tiny lobster-looking crustacean possibly could be. But we know of one kind that's different.

Marmorkrebs, otherwise known as "marbled crayfish", didn't form naturally in the wild. They're an offshoot of a North American crayfish species called Procambarus fallax that surfaced in the pet trade, and they're distinct in the way they reproduce through parthenogenesis, otherwise known as cloning themselves.

And they clone themselves extensively, to the point where a single marbled crayfish which a pet owner released into the wild could create an entire population of clones entirely on their own. Which is exactly what happened in places like Madagascar and Germany, where Marmokrebs are now an invasive species that keep sprouting out offshoots of themselves two to three times per year.

The news broke after a team of researchers analyzed 11 marbled crayfish, a mix of pets and wild specimens, and found that their genomes were all identical. And they're all female as well since every member of the species can be traced back to a single female crayfish which began spawning them.

And now, a single crayfish can create hundreds of clones throughout its life, leading to the species' invasive qualities as soon as one escapes outside. Frank Lyko of the German Cancer Research Center explained in a press release:

Opening quote
"It was known that the crayfish can establish itself in the wild after releases from the aquarium. But the news was that it can spread so rapidly and massively."
Closing quote

Initially, this seemed like more of a curse than a blessing to the marbled crayfish—one of the benefits of sexual reproduction (from an evolutionary standpoint) is that it allows for more genetic variation, and that's the cornerstone of natural selection, where an animal with the most beneficial mutations gets to pass on those genes as the species evolves. When every member of a species is an identical clone, there's no competition.

But the marbled crayfish seem to be managing just fine without sex. The species is surprisingly adaptable, having established themselves in such wildly different climates like Madagascar, Germany, Sweden, and Japan. The researchers now suspect that there's millions of clones around the world by this point.

So don't release your pet crayfish into the wild, unless you're sure it won't start taking over its environment with identical copies of itself.
Science News