Evolving Humans

 
Nicholas Wade is often considered to be one of the best science journalists. He writes for The New York Times. His latest article is: Adventures in Very Recent Evolution. Here's one paragraph.

Many have assumed that humans ceased to evolve in the distant past, perhaps when people first learned to protect themselves against cold, famine and other harsh agents of natural selection. But in the last few years, biologists peering into the human genome sequences now available from around the world have found increasing evidence of natural selection at work in the last few thousand years, leading many to assume that human evolution is still in progress.

Later on in the article, Wade seems to be aware of the other mechanism of evolution but here he equates "evolution" with "natural selection." What do we have to do in order to educate science journalists? [Have Humans Stopped Evolving?] [Did biologists really think that human evolution stopped?]

Anyone who assumed that "humans ceased to evolve in the distant past" simply doesn't understand evolution. You can't stop evolution.

The main thrust of the article is whether natural selection is having a significant impact on our genetic makeup. There are many biologists who support the idea that more than 10% of our genes (alleles) are under selection and most of these biologists think that evolution by natural selection may even have sped up in the past 10,000 years.

John Hawks is a proponent of recent rapid human evolution by natural selection¹ and, as expected, he has a post discussing The New York Times article [Recent selection, the new paradigm ]. I'm still pretty skeptical of those studies that claim to detect selection by analyzing genomes. I find the lack of agreement between different studies much more troubling than John does.

Recent talks and posters at the Society for Molecular Biology and Evolution meeting (SMBE 2010) highlighted some of the problems. Some emphasized the large number of false positives² in published studies and questioned the accuracy of the algorithms. Others pointed out that biased gene conversion at recombination hotspots may be much more frequent that we assumed and this gives the appearance of selective sweeps when, in fact, the alleles being enriched may be neutral or even detrimental.

Since john hawks weblog doesn't have a comments section I thought you readers might like to discuss it here.

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Photo Credit: The Future of Human Evolution [Aaron Avivi].

1. See Examples of Accelerated Human Evolution.

2. See Signals of Positive Selection in Humans?.