Talk:Evolution of the brain
|WikiProject Neuroscience||(Rated Start-class, High-importance)|
There is a related discussion at Wikipedia talk:WikiProject Neuroscience#Brain size and Human brain size. --Tryptofish (talk) 20:07, 8 September 2014 (UTC)
Genetic Factor contributing to modern evolution
Bruce Lahn, the senior author at the Howard Hughes Medical Center at the University of Chicago and colleagues have suggested that there are specific genes that control the size of the human brain. These genes continue to play a role in brain evolution, implying that the brain is continuing to evolve. The study began with the researchers assessing 214 genes that are involved in brain development. These genes were obtained from humans, macaques, rats and mice. Lahn and the other researchers noted points in the DNA sequences that caused protein alterations. These DNA changes were then scaled to the evolutionary time that it took for those changes to occur. The data showed the genes in the human brain evolved much faster than those of the other species. Once this genomic evidence was acquired, Lahn and his team decided to find the specific gene or genes that allowed for or even controlled this rapid evolution. Two genes were found to control the size of the human brain as it develops. These genes are Microcephalin and Abnormal Spindle-like Microcephaly (ASPM). The researchers at the University of Chicago were able to determine that under the pressures of selection, both of these genes showed significant DNA sequence changes. Lahn's earlier studies displayed that Microcephalin experienced rapid evolution along the primate lineage which eventually led to the emergence of Homo sapiens. After the emergence of humans, Microcephalin seems to have shown a slower evolution rate. On the contrary, ASPM showed its most rapid evolution in on the later years of human evolution once the divergence between chimpanzees and humans had already occurred. .
Each of the gene sequences went through specific changes that lead to the evolution of humans from ancestral relatives. In order to determine these alterations, Lahn and his colleagues used DNA sequences from multiple primates then compared and contrasted the sequences with those of humans. Following this step, the researchers statistically analyzed the key differences between the primate and human DNA to come to the conclusion, that the differences were due to natural selection. The changes in DNA sequences of these genes accumulated to bring about a competitive advantage and higher fitness that humans possess in relation to other primates This comparative advantage is coupled with a larger brain size which ultimately allows the human mind to have a higher cognitive awareness. . — Preceding unsigned comment added by Solanki.15 (talk • contribs) 20:55, 17 November 2014 (UTC)
Missing sources in part 1
There are two sources mentioned in part 1: ´´Hoffman et al. 2004´´ and ´´Hofman 2001´´, but they are not quoted in a section literature or similar. Quite difficult to find the sources without being the author of this wikipedia article. DinoDinoDinoDinoDino (talk) 11:12, 10 December 2014 (UTC)
- Dorus S., Vallender E.J., Evans P.D., Anderson J.R., Gilbert S.L., Mahowald M., Wyckoff G.J., Malcolm C.M., Lahn B.T. 2004. Accelerated evolution of nervous system gene in the origin of homosapiens. Cell. 119(7):1027-40.
- Evans P.D., Gilbert S.L, Mekel-Bobroz N., Vallender E.J., Anderson J.R. Vaez-Azizi L.M., Tishkoff S.A., Hudson R.R. and Lahn B.T. 2005. Microcephalin, a Gene Reulating Brain Size, Continues to Evolve Adaptively in Humans. Science 309(5741):1717-20