Noise Between the Nature Versus Nurture Debate

1990. An army of marbled crayfish clones invaded the land of Germany. Within just a decade, these lobster-like creatures would be found invading other countries like Italy, Croatia, Slovakia, France, Sweden, and Japan. How were these crayfish able to clone themselves? The answer, according to scientists, might dat back to 1995.

Scientists suspect that sometime around 1995, a genetic mutation allowed a pet crayfish to reproduce asexually, giving rise to a new, all-female species that could make clones of itself from its unfertilized eggs. Deliberately or accidentally, some of these mutants were released from aquariums into the wild, where they rapidly multiplied into the millions, threatening native waterways species and ecosystems.

But their success is strange. “All marbled crayfish which exist today derive from a single animal,” said Günter Vogt, a biologist at Heidelberg University. “They are all genetically identical.” Ordinarily, the absence of genetic diversity makes a population exceedingly vulnerable to the vagaries of its environment. Yet the marbled crayfish have managed to thrive around the globe.

A closer look reveals that the crayfishes’ uniformity is only genome-deep. According to studies conducted by Vogt and others in the mid-2000s, these aquatic clones actually vary quite a bit in their color, size, behavior and longevity. Which means that something other than their genes is inspiring that diversity.

So what contributes to the diversity of these crayfish clones? If it is not nature, then the usual response would be nurture. At least that’s what our common sense would deduce. But new research on crayfish and other organisms reveal something else other than nature and nurture, and that is “random, intrinsic noise”.

More details about this over at Quanta Magazine.

(Image Credit: Zfaulkes/ Wikimedia Commons)