Are we humans simply remodelled apes? Chimps with a tweak? Is the difference between our genomes so minuscule it justifies the argument that our cognition and behaviour must also differ from chimps by barely a whisker? If “chimps are us” should we grant them human rights? Or is this one of the biggest fallacies in the study of evolution? NOT A CHIMP argues that these similarities have been grossly over-exaggerated - we should keep chimps at arm’s length. Are humans cognitively unique after all?
Tuesday, 23 February 2010
We Still Can't Explain Biology With Molecules
A nice little head-scratching type of essay by Michael White. How did changes at the level of the molecular sequence structure of our genes, or the levels of gene expression, actually make us human - or, more precisely, how do they actually account for the phenotypic differences between us and the main comparison species - the chimpanzee? White quotes Gregory Wray (see NOT A CHIMP) who has proved King and Wilson's theory that changes in gene expression count more than nucleotide substitutions in the sequence of genes. What were all these genes with elevated expression levels doing in human brains? White quotes Wray: "Differentially expressed tags within coding regions are enriched for gene functions involved in synaptic transmission, transport, oxidative phosphorylation, and lipid metabolism". What can you actually do with this list of genes, and gene function, asks White. How do differences in these sorts of functions make us a human and not a chimp?
Small Dogs Originated In The Middle East
In my chapter THE APE THAT DOMESTICATED ITSELF I go into some detail about proposed routes to the domestication of dogs. The most popular theory at the moment is that dogs began the process of their own domestication through selection for the tolerance of the proximity of man while scrounging around early human encampments and villages. But the big question mark hangs over precisely which species of wolf was the progenitor. Some researchers claim it was the gray wolf while others, claiming the gray wolf was too big, have elected for a smaller Asian wolf, or several progenitors rather the same size as present day jackals, in order to accommodate the decrease in size for most dogs compared with wolves. Now Robert Wayne and Melissa Gray, two prominent genetics researchers in this area, have come up with a proposal that the gray wolf was indeed the ancestor but that the preliminary evolutionary processes of domestication favoured the selection of a gene, IGF1, which is a determinant of small size.