Archive for the 'Genetics' Category

Hear a Neanderthal Talk (and Other Interesting Neanderthal Language Rumblings)

Anthropology.net and New Scientist have recently reported on a couple of developments in the Neanderthal language debate.
Firstly, a new paper is in the works that will cast doubt upon the conclusions of the now famous Neanderthal FOXP2 paper from last year. Krause et al found the same adaptive variation of the language-implicated FOXP2 gene as is found in humans in Neanderthal DNA sequences, and claimed that the this was evidence for FOXP2 as a homologous trait that was present in our common ancestor. Cue endless headlines about how this finding is proof that Neanderthals had language.

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Evolang 08 – Plenary Speakers Day 2

The next day brought a couple of plenary speakers who both spoke on fascinating topics but somehow managed to make them dull as hell or inpenetratable.

Rudolph Botha began by looking at exaptation and argued that it is a mechanism that is too frequently employed in accounts of language evolution. He painstakingly went through a series of examples in the literature where exaptation is heavily invoked and tried to show that it did not meet the standards for exaptation that most biologists would use. It was persuasive, and on an interesting topic, but somehow Botha contrived to make it duller than a Calvinist sermon. Come on Rudi, this subject is naturally cool, it shouldn’t have the life sucked out of it like this.

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New PLoS Research Argues for Grammar-Specific Areas in the Brain

This interesting new paper by Fonteneau & van der Lely presents evidence that there is some specific language structure in the brain that deals with syntactic processing. They present evidence from children with SLIs (Specific Language Impairments); a condition that affects up to 7% of children and causes devlopmental problems in the children’s language learning. Interestingly there is increasing evidence that this linguistic impairment has a genetic basis. The research used novel electrophysiological data to demonstrate that the grammar impairment had a neurological basis.

“The findings indicate that grammatical neural circuitry underlying language is a developmentally unique system in the functional architecture of the brain, and this complex higher cognitive system can be selectively impaired… The results argue for grammar being a highly specific, specialised subsystem in the human brain and a particular developmental pathway to this exclusive neural system.”

They make an explicit link between this evidence and the debate in evolutionary linguistics about the the extent to which syntactic knowledge is represented in the brain. Yet more evidence that language is innate, but as has been mentioned before, innateness of the language faculty, and innateness of the rules of grammar, are not the same thing. I hope there will be more neurobiological evidence like this presented in future.

Humans evolve fastest – The gap with Chimpanzees widens

Recent research demonstrates that the speed with which humans acquire and ditch new genes is the fastest yet studied in mammals.  Primates are noticeably quick at genetic variation, but humans are the fastest of all, meaning that the eternally quoted “Chimps share 97 % (or 98%, take your pick) of our DNA” does not tell the whole story about genetic difference. Whilst they may share 97% of our nucleotide sequences, the differences in quantities of this gene may indicate a more notable genetic difference. According to this Science article “6.4% of the 22,000-odd human genes aren’t present in chimps” making the difference between them seem considerably larger.

Armand Leroi – What Makes Us Human

Here is a high quality copy of the second part of Armand Leroi‘s acclaimed What Makes Us Human? documentary. It’s a little shallow in its representation of the issues and occasionally might have you screaming at the screen in frustration. (Pinker’s misrepresentation of the Chimpanzee language research programme had the veins popping in my neck). Overall however, it is a very good overview of all the most popular ideas in the field and is packed with great footage of Alex the Parrot, children with FOXP2 abnormalities, studies into autism and an exploration of mirror neurons. Requires the DIVX codec

Enjoy.

New FOXP2 Developments

Just following on from the comments on the last FOXP2 post. A new paper (Li G, Wang J, Rossiter SJ, Jones G, Zhang S, 2007) has revealed that FOXP2, a gene sequence implicated in the development language, is also rapidly evolved in echo-locating bats. Most vertebrates possess FOXP2, but several recent papers it was thought that only humans had significant species difference in the gene, being a full two amino acids different from chimpanzees. Given that this gene was implicated in both speech motor coordination and comprehension, it was felt that this was the first major example of a language gene – a gene heavily responsible for our evolved capacity for language.

This new paper follows in the line of some other recent papers that have shown FOXP2 manipulations in other animals, and which have suggested that FOXP2 is not a language gene per se, but a gene implicated in sophisticated communication and vocal production. The researchers sequenced the gene in both echolocating and non-echolocating bat species and found evidence of divergent selection and accelerated FOXP2 evolution compared to other vertebrates. Interestingly they performed a similar survey of cetations and found no significant results.

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