Philipp Khaitovich of the Partner Institute for Computational Biology in Shanghai, China, and colleagues analysed brain tissue from deceased humans, chimpanzees and rhesus macaques to study the concentrations of 100 chemicals linked with metabolism.
In the human prefrontal cortex, the levels of 24 of these were drastically different from levels in the corresponding brain regions of the other primates. In the cerebellum, however, there were far fewer differences between humans and the other animals, with just six chemicals showing different concentrations.
This suggests that, since our lineage split off from other primates, the evolution of metabolism in the thinking and learning parts of our brains has gone much further than in our “primitive” cerebellum.
I wonder if “‘primitive’ cerebellum” will go the way of “junk” DNA?
The authors may think (they don’t say so directly) that differing brain chemistry is a cause of higher order thinking. It could just as easily be interpreted as a platform for higher order thinking, or even as a consequence of it.
Excerpt: If the error structures of the archaic DNA and one of the modern human DNA samples are similar to each other for one of many reasons, the ABBA-BABA test could report admixture when it did not in fact occur. Even a very small proportion of shared errors could cause a strong effect on the ABBA-BABA statistic. For example, small effects that we typically tend to ignore, such as shared contamination of reagents between the samples, could cause artifactual evidence of admixture.
In this podcast Dr. Patricia Fanning examines the evolutionary claim that humans evolved more sophisticated brains as a result of chemicals other primates did not have.
Story Credit here and video