Motus Mentis

My friend Jess Kaplan, who often sends me interesting tidbits, has called my attention to a curious item from Turkey. It’s a story about a group of siblings who, some are saying, are examples of retrograde evolution.

The case, which you can read about here, involves a Kurdish family with nineteen children. Five of them, three daughters and two sons, carry a genetic anomaly that results in an unusual suite of symptoms. To begin with, they are all mentally retarded, and they share a language of their own creation, consisting of a few hundred words. But the most striking effect of their abnormal genome is that they walk on all fours, using their feet and the palms of their hands. Two of them, one son and one daughter, are able to stand upright for brief periods, with knees flexed and head dropped forward, but the others can’t even manage that. You can see a brief video clip here.

The mutation has been identified; it is located in an area called “chromosome 17p”, which is where some other major distinctions between the human and chimpanzee genomes are found.

So is this really “devolution”? It seems that some are quick to assert that it is, but I wonder. Our closest primate relatives don’t walk on their palms like these people do, but rather on their knuckles. An article about the family in England’s Daily Mail says “Scientists believe this may be the way hominids moved to protect their fingers for more delicate movements“, but if so, that’s the first I’ve heard of such a thing.

Might it not be that these atavistic Anatolians simply have some sort of damage to the information in the chromosome 17p area (which is also associated with bipedalism), without it necessarily being a reemergence of an ancient and deeply buried gene? The gait exhibited in the video clip hardly looks adaptive, though I admit that perhaps an ancient mode of locomotion is in this case being imposed on a modern frame, with ungainly results.

I imagine more information will be trickling in, if we keep our ears close to the ground. In fact, I did a record project once with some folks who might be able to shed more light on all of this.