http://www.pnas.org/content/109/40/16389.abstract.html?etoc
A few days ago I posted about the New Zealand research group who have claimed that New Caledonian crows can infer the causal role of hidden agents. This is now an open access paper in PNAS and the link to it is above.
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, 2 October 2012
Scientists find homolog of mammalian neocortex in bird brain
http://phys.org/news/2012-10-scientists-homolog-mammalian-neocortex-bird.html
In the chapter CLEVER CORVIDS in NOT A CHIMP I relay Nathan Emery's complaint that the brains of birds have been given short shrift in comparative biology. He points out that both birds and mammals have an embryonic brain region - the telencephalon - that can give rise to comparable structures. Furthermore, the cognitive feats of corvids allow them to shrug off the discouraging moniker "bird brains" for ever. Now scientists at Chicago have found an area of nuclei in the dorso-ventricular ridge in bird brains that behave very much like the neocortex in mammals.
In the chapter CLEVER CORVIDS in NOT A CHIMP I relay Nathan Emery's complaint that the brains of birds have been given short shrift in comparative biology. He points out that both birds and mammals have an embryonic brain region - the telencephalon - that can give rise to comparable structures. Furthermore, the cognitive feats of corvids allow them to shrug off the discouraging moniker "bird brains" for ever. Now scientists at Chicago have found an area of nuclei in the dorso-ventricular ridge in bird brains that behave very much like the neocortex in mammals.
Monday, 1 October 2012
A Comparison of Brain Gene Expression Levels in Domesticated and Wild Animals
http://www.plosgenetics.org/article/info%3Adoi%2F10.1371%2Fjournal.pgen.1002962
When I wrote NOT A CHIMP, Frank Albert, at the Max Planck Institute for Evolutionary Anthropology, was just beginning to cross rats to produce a violently feral strain and a docile, more domesticated behavioural variant. He hoped to be able to find genes that underlie these traits and, eventually, to compare genes that seem important in, say, rat domestication, with genes important in domesticated traits in other species. Is there a universal genetic foundation for domestication throughout the animal kingdom? Here, in this open access PLoS Genetics paper, he presents his results for rats, compared with wild and domesticated representatives from a range of species. "We used mRNA sequencing to analyze genome-wide gene expression patterns in brain frontal cortex in three pairs of domesticated and wild species (dogs and wolves, pigs and wild boars, and domesticated and wild rabbits). We compared the expression differences with those between domesticated guinea pigs and a distant wild relative (Cavia aperea) as well as between two lines of rats selected for tameness or aggression towards humans."
Unfortunately there was no evidence at all for such universal genetics: "There were few gene expression differences between domesticated and wild dogs, pigs, and rabbits (30–75 genes (less than 1%) of expressed genes were differentially expressed), while guinea pigs and C. aperea differed more strongly. Almost no overlap was found between the genes with differential expression in the different domestication events. In addition, joint analyses of all domesticated and wild samples provided only suggestive evidence for the existence of a small group of genes that changed their expression in a similar fashion in different domesticated species."
He concludes: "In summary, the majority of brain gene expression changes in domesticated animals are specific to the given domestication event, suggesting that the causative variants of behavioral domestication traits may likewise be different."
When I wrote NOT A CHIMP, Frank Albert, at the Max Planck Institute for Evolutionary Anthropology, was just beginning to cross rats to produce a violently feral strain and a docile, more domesticated behavioural variant. He hoped to be able to find genes that underlie these traits and, eventually, to compare genes that seem important in, say, rat domestication, with genes important in domesticated traits in other species. Is there a universal genetic foundation for domestication throughout the animal kingdom? Here, in this open access PLoS Genetics paper, he presents his results for rats, compared with wild and domesticated representatives from a range of species. "We used mRNA sequencing to analyze genome-wide gene expression patterns in brain frontal cortex in three pairs of domesticated and wild species (dogs and wolves, pigs and wild boars, and domesticated and wild rabbits). We compared the expression differences with those between domesticated guinea pigs and a distant wild relative (Cavia aperea) as well as between two lines of rats selected for tameness or aggression towards humans."
Unfortunately there was no evidence at all for such universal genetics: "There were few gene expression differences between domesticated and wild dogs, pigs, and rabbits (30–75 genes (less than 1%) of expressed genes were differentially expressed), while guinea pigs and C. aperea differed more strongly. Almost no overlap was found between the genes with differential expression in the different domestication events. In addition, joint analyses of all domesticated and wild samples provided only suggestive evidence for the existence of a small group of genes that changed their expression in a similar fashion in different domesticated species."
He concludes: "In summary, the majority of brain gene expression changes in domesticated animals are specific to the given domestication event, suggesting that the causative variants of behavioral domestication traits may likewise be different."