Chimps Use Cleavers And Anvils As Tools To Chop Food

Interesting piece about the observations of Kathelijne Koops, together with Bill McGrew and Tetsuro Matzuzawa, on novel tool use of the chimps in the Nimba Mountains of Guinea. Because the Treculia fruits they are so fond of are very large - the size of a volleyball and weighing up to 8.5 kilos - they cannot access the food by biting into it. They use a variety of stone and wooden cleavers to splinter the fruit into manageable pieces on stone anvils. The practice is very local to this group of chimps - a local culture - and is not shared, for example, by the neighbouring Seringbara chimps.

When Fire Approaches, Chimps Keep Their Cool

Interesting article in SCIENCENOW about the work of primatologist Jill Pruetz with the Fongoli chimps, regarding their behaviour toward fire. Instead of panicking and totally failing to comprehend the nature of fire, she noted that the chimps reacted to brush fires by carefully forging paths to avoid the outbreaks. If you allow that human mastership of fire required three stages: conceptualizing it (meaning also to lose fear of it); starting it; and containing it, Preutz argues, you can see chimp behaviour, perhaps, as a clue as to how some putative hominin ancestors reacted to fire, which eventually led to employing fire to cook food etc. I always have a problem with "chimps give clues to origins of human behaviour" stories because we did not evolve from them. So, if the logic is defensible it is only by virtue of arguing that chimps retained some vestige of loss of fear of fire that was present in the common ancestor of chimps and humans.

Microcephaly Genes Associated With Human Brain Size.

In the third chapter of NOT A CHIMP I explain that Bruce Lahn's "quick and dirty" route to human brain evolution, based on the recent selection of variants for two genes associated with microcephaly, foundered because a number of research groups around the world, including his own, could find no links between variants of these genes and measurements of brain size in modern populations. However, this group has found a new and much more accurate way of measuring cortical surface area and they report significant associations between C.S.A. and variants of the CDK5RAP2 gene involving changes to its regulatory region. They conclude: "One particularly interesting feature of this new discovery is that the stronger links with cortical area were found in regulatory regions, rather than in the coding regions of the genes. One upshot of this may be that in order to further understand the molecular and evolutionary processes that have determined human brain size, we need to focus on regulatory processes rather than further functional characterization (changes in amino-acid sequence) of the proteins of these genes. This has huge implications for future research on the links between genetics and brain morphology."

This group did not, it appears, attempt to discover the age of the evolution of the regulatory variants they examined but it will be very interesting if they choose to investigate ASPM and Microcephalin, the two genes Lahn worked on and which tipped him into hot political water!

Does Culture Prevent Or Drive Human Evolution?

In the penultimate chapter of NOT A CHIMP I argue the case for accelerated recent human evolution, including the claim, from genome-wide trawls for signatures of selection, that as much as 10% of the human genome has undergone evolution within the last 40,000 years or less. In other words, that human demographic and cultural movement into new latitudes and geographical parts of the earth, allied to innovations such as villages and, eventually, conurbations; agriculture; and technology, have imposed a totally new set of selection pressures on human populations. A scenario in which gene-culture interactions become predominant. Here, molecular anthropologist Mark Stoneking, debates the idea, sympathetically, in a recent essay. The comments that follow are also essential reading.

The Looming Crisis In Human Genetics

Just spotted this November-dated essay in The Economist from my friend Geoffrey Miller. He provocatively claims that the crisis (for liberals) will arise in 2010 because GWAS (genome wide association studies) will turn out to tell us less about the genetic causes of mankind's diseases than the genetic variants and associations that underpin widespread genetic variation across races, ethnicities and regions. More trouble for "all men were created equal" ideologues. As Miller concludes: "If the shift from GWAS to sequencing studies finds evidence of such politically and morally perplexing facts, we can expect the usual range of ideological reactions, including nationalistic retro-racism from conservatives and outraged denial from blank-slate liberals. The few who really understand the genetics will gain a more enlightened, live-and-let-live recognition of the biodiversity within our extraordinary species - including a clearer view of likely comparative advantages between the world's different economies." Miller cites the work by Greg Cochran and Henry Harpending (which, together with work they have published in cahoots with John Hawks and Robert Moyzis) is amply referred to in the penultimate chapter of Not A Chimp - that some human groups have experienced a vastly accelerated rate of evolutionary change within the last 10,000 years - whereas others have not.

Symbolic Gestures And Spoken Language Processed By Common Neural System

Back in the saddle after the Christmas break and catching up on a few interesting items. This PNAS paper, which includes Pat Gannon as an author, compares the areas of the human brain that light up when the subject is presented with symbolic gestures, like pantomimes of actions like threading a needle, or emblems that have social significance like finger to lips to indicate "be quiet", with the speech equivalents. Both classes of stimuli, they report, activate a common left-lateralized network of perisylvian areas of temporal lobe. Their abstract concludes thus: "We suggest that these anterior and posterior perisylvian areas, identified since the 19th century as the core of the brain's language system, are not in fact committed to language processing, but may function as a modality-independent semiotic system that plays a broader role in human communication, linking meaning with symbols whether these are words, gestures, images, sounds or objects."