11 Nov 09 – “Two minute changes in a gene that is otherwise identical in humans and chimps could explain why we have full-fledged power of speech while other primates can only grunt or screech,” says this article on Yahoo. “Human speech is thought to have emerged 100,000 to 200,000 years ago.”
A decade ago, investigators found that a small number of patients with speech-related diseases all shared the same defect in a gene called FOXP2.
Different researchers studying FOXP2 in chimpanzees noticed that only two among the hundreds of amino acids in the protein coded by the gene differed across the two species.
Daniel Geshwind, a professor at UCLA, designed the first-ever experiments comparing the FOXP2 in chimps with humans.
“FOXP2 drives these genes to behave differently in the two species,” said Geschwind.
In humans, the gene triggers changes in the parts of the cerebral cortex that control high cognitive functions and language. It also affects the striatum, which is involved with motor coordination.
But even if one could transplant a human brain into a chimpanzee, the ape would probably be unable to speak because it lacks the right “articulatory apparatus,” said Geschwind.
The study is published in the British science journal Nature.
See entire article, entitled “Tiny evolutionary mutation led to ‘language gene'”:
Thanks to David Bass in Australia for this link