You can’t have so many random mutations in such a short time to go from 10% to 30% in 130 years. Must be a different mechanism. Could be food, could be higher likelihood of early childhood death in the past, could be environment/exposure. If not through methylation this is probably actually a step backwards. Cause and effect are also unclear. There may well be an underlying mechanism that has consequences other than survival chances because of changes in the forearm.

as per ScienceFan's comment - Article doesn't say how natural selection is working here, its highly unlikely that those with the median artery get a lot better chance of surviving and reproducing than those that don't. So be interesting to to know what mechanism is occurring here, environmental? If so, is the mechanism causing other mutations?

This trait had to begin somewhere and spread from there... most likely due to the greater intermingling of populations since the start oof the industrial age.

Survival of the fittest as long been abandoned in our species, so has nay kind of selection. Humans are not very particular about who they are having children with. Like in the movie Idiocracy, the uneducated, unhealthy and un-intelligent reproduce at a grater rate. This new mutation is most likely a function of no selection.

If this is indeed an inherited genetic feature, and one where to investigate the changes in the genes involved, I would predict that this is the result of a degenerative mutation, in other words, a loss of genetic specificity. It is also unclear how natural selection could select for this particular mutation. However, if this is caused by a loss of information and is inherited, it is clearer how it could be increasing in the population regardless of whether or not it increases fitness.

In addition to my previous comment*

Similar to how you can breed wolves to chihuahuas but you can't breed chihuahuas back to wolves because selective breeding to chihuahuas involves a loss of genetic information.

Now if we could just manage a few extras around the old ticker, we might corral heart disease...

At such a rate, I predict humans will have extra thumbs in 150 years from 29 June, 2007.

From ultrasound scans, I have been told that I have THREE kidneys, which although unusual is not unknown. What genetic advantage does this give ME? Well, one thing, is that I can, apparently, process alcohol more efficiently. I once drank a full bottle of whisky in an evening with NO noticeable ill effects whatsoever. Even when I do drink too much too fast, any effects disappear very rapidly. I've only ever had one hangover, and that was from mixing the grain and the grape, brandy and whisky combined, and in my early youth, one event that got me 'paralytic' and that took about a litre of mixed spirits, within a couple of hours, but no hangover! My paternal grandfather died from cirrhosis, so maybe that triggered my genetics to improve my alcohol processing. Who Knows? It's been shown, that in a Finnish village that suffered a famine, the grandchildren, and onwards still showed the effects in their genome 'tabs'. 'Tabs' (my term) are bits that used to be regarded as 'junk' until research and intelligence proved otherwise. I think the human body is far more complex than even most researchers realise, and the return of a past characteristic, is probably due to unnoticed environmental factors. After all, life has had hundreds of millions of years to develop. Human research into it, only maybe thousand or so.

When an animal is domesticated, youthful traits tend to persist throughout its life. People use breeding selection to domesticate animals and we are doing the same, not so much by deliberate and controvercial ideas like eugenics, but we do it, nevertheless, unintentionally, by creating environments where people are more (or less) likely to procreate, based on variouis inherited traits. People who mature quickly and completely are more likely to think for themselves and cause trouble, which is discouraged in the "rat-race". People are encouraged to try to be as young as you can be for as long as you can at the expense of needed maturation. Then there's Hollywood's obsession with "little girls". Yea, there's a eugenics program going on, implemented by a mob of people and companies, not so much with any central control....taming the sheeple.