The marbled crayfish are born pregnant just like fictional Star Trek Tribbles

The marbled crayfish is a mutant species that clones itself, scientists report. The population is exploding in Europe, but the species appears to have originated only about 25 years ago. Ranja Andriantsoa
The Marbled crayfish lays eggs without mating. The progeny were all female, and each one grew up ready to reproduce. This is similar the classic Star Trek Episode the Trouble with Tribbles. Tribbles are born pregnant which is quite a time saver.

In 2003, scientists confirmed that the marbled crayfish were indeed making clones of themselves. They sequenced small bits of DNA from the animals, which bore a striking similarity to a group of crayfish species called Procambarus, native to North America and Central America.

For nearly two decades, marbled crayfish have been multiplying like Tribbles on the legendary “Star Trek” episode. “People would start out with a single animal, and a year later they would have a couple hundred,” said Dr. Lyko.


The scientists concluded that the new species got its start when two slough crayfish mated. One of them had a mutation in a sex cell — whether it was an egg or sperm, the scientists can’t tell.
Normal sex cells contain a single copy of each chromosome. But the mutant crayfish sex cell had two.

Somehow the two sex cells fused and produced a female crayfish embryo with three copies of each chromosome instead of the normal two. Somehow, too, the new crayfish didn’t suffer any deformities as a result of all that extra DNA.

It grew and thrived. But instead of reproducing sexually, the first marbled crayfish was able to induce her own eggs to start dividing into embryos.

The movie Jurassic Park also had as a plot point that an all-female population of dinosaurds would find a way to breed.