Variation in evolution

Marmorkrebs make a brief cameo appearance in this article in New Scientist on the importance of variation in evolution. It’s behind a registration wall, unfortunately, and will disappear to a “subscribers only” section in a few days, so catch it while you can. But here’s the relevant excerpt:

Is this “uncertainty hypothesis” right? There is evidence that epigenetic changes, as opposed to genetic mutations or environmental factors, are responsible for a lot of variation in the characteristics of organisms. The marbled crayfish, for instance, shows a surprising variation in coloration, growth, lifespan, behaviour and other traits even when genetically identical animals are reared in identical conditions. And a study last year found substantial epigenetic differences between genetically identical human twins. On the basis of their findings, the researchers speculated that random epigenetic variations are actually “much more important” than environmental factors when it comes to explaining the differences between twins (Nature Genetics, vol 41, p 240).