This week, Muller’s Ratchet:
In evolutionary genetics, Muller’s ratchet (named after Hermann Joseph Muller) is the name given to the process by which the genomes of an asexual population accumulate deleterious mutations in an irreversible manner (hence the word ratchet). The genomes of sexual populations can easily reverse this process thanks to recombination. Continued [...]
Norton et al in Mol. Biol. Evol. use data from the International Hapmap project (which we covered earlier) to test 6 human skin pigmentation genes for positive directional selection. They argue that this shows a pattern of convergent evolution towards ligter skin pigmentation in Europeans and East Asians. Abstract here
Morrell and Clegg in today’s P.N.A.S. investigated differences in haplotype frequency in multiple loci over > 60 Barley species. They argue that this demonstrates that Barley (Hordeum vulgare) was domesticated twice. It was first cultivated in the Fertile Crescent, which lead to most of the current European and American cultivars. The second domestication [...]
Stefan Lovgren in National Geographic:
The so-called Clovis people, known for their distinctive spearheads, were not the first humans to set foot in the Americas after all, a new study says. The find supports growing archaeological evidence found in recent years that disputes the notion that the Americas were originally populated by a single [...]
Hobolth et al in PLoS Genetics have re-estimated the date of the chimp-human split using a Coalescent Hidden Markov Model, and infer ancient population sizes of the species in question. The author’s summary:
Primate evolution is a central topic in biology and much information can be obtained from DNA sequence data. A key parameter is [...]
There’s been a few brief reports recently that chimpanzees have been seen hunting bushbabies with spears (primatology.org, LiveScience), and today the paper on this by Preutz and Bertolani can be found in press at Current Biology:
Although tool use is known to occur in species ranging from naked mole rats to owls, chimpanzees [...]
There’s a nice article on stress in ScienceDaily:
Why do humans and their primate cousins get more stress-related diseases than any other member of the animal kingdom? The answer, says Stanford University neuroscientist Robert Sapolsky, is that people, apes and monkeys are highly intelligent, social creatures with far too much spare time on their hands.
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This week’s Wednesday wiki page is on Coalescent Theory:
coalescent theory states that all genes or alleles in a given population are ultimately inherited from a single ancestor shared by all members of the population, known as the most recent common ancestor. If the inheritance relationships are written in the form of a phylogenetic [...]
From the always interesting Neatorama, the world’s Strangest Dinosaur names:
JURASSOSAURUS NEDEGOAPEFERIMA
Ah, the (limited) power of money: Steven Spielberg, who gave money toward Chinese dinosaur research, suggested the name Jurassosaurus after his 1993 blockbuster movie Jurassic Park. The species name nedegoapeferima is formed from the surnames of the movie’s main stars: Sam [...]
