Friday, February 18, 2011

This week in human origins

This has been a busy week for interesting articles on human origins. First, PNAS published a very interesting paper on Alu elements, which are primate-specific transposable elements. Seems the human genome has a lot of Alus in actual gene coding sequences. I'm sure that news will make a lot of creationists happy. Shen et al.'s paper is open access, so everybody can read it:

Shen et al. 2011. Widespread establishment and regulatory impact of Alu exons in human genes. PNAS 108:2837-2842.

Then Nature published a review article by Bernard Wood and Terry Harrison on human evolution. It's nothing earth-shatteringly new, but it is consistent with Wood's skepticism about the ability of cladistics to resolve the phylogeny of hominin fossils. Specifically in this paper, they're trying to challenge the classification of Ardipithecus, Sahelanthropus, and Orrorin as hominins, or at the very least suggest that those three taxa may not obviously be hominins. They have a pretty dim view of applying cladistics to paleoanthropology, at least at this stage in our understanding.

Wood and Harrison. 2011. The evolutionary context of the first hominins. Nature 470:347–352.

And finally Science published a new paper from Hernandez et al. on selective sweeps in human evolution. They looked at variation in 179 human genomes and concluded,
These findings indicate that classic sweeps were not a dominant mode of human adaptation over the past ~250,000 years.
Hernandez et al. 2011. Classic Selective Sweeps Were Rare in Recent Human Evolution. Science 331:920-924.

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