大脑进化 z-bo 2020-09-24 385

　　In the process of human origin, the rapid expansion of brain power has always been a central issue in the study of primate brain evolution. Previous studies have mainly compared the differences in brain volume between humans and non-human primates and their genetic regulation mechanisms, but there are few genetic analyses on population-level brain volume changes during modern human evolution. Did not participate.

　　The Su Bing Institute (research assistant Shi Lei, master student Hu Enzhi) of the Kunming Institute of Zoology, Chinese Academy of Sciences discovered in a recent study that the brain volume regulator CASC5 had 8 amino acid mutations during the origin of modern humans. I found myself accumulating. Except for these mutant humans and ancient humans (Nean Deltars and Denisobans), it does not exist in primates, and it is a unique mutation site for modern humans. Among them, two mutation sites are fixed in modern people, but the other six sites are still polymorphic in the population. What's more interesting is that these four polymorphic loci show a higher frequency in the East Asian population, but show a very low frequency in the European and African populations. Further molecular evolution analysis showed that the CASC5 gene was affected by Darwin’s positive selection in East Asian populations, but no selection signal was found in African and European populations. Genetic association analysis showed that these abundant loci in East Asian populations were significantly related to the amount of gray in the brains of Han people, and carriers of allogeneic mutations had greater amounts of gray. I proved it. The results of this study indicate that the CASC5 gene may play an important role in the morphological changes of the modern human brain during the recent evolution of the modern human brain.