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Terahara, M.

Publications and source records attributed to Terahara, M..

2 recordsLinked to original sources

Global adaptive evolution involved in neuroticism and educational behaviors through the spread of anatomically modern humans

A cumulative process of cultural evolution occurred globally alongside the spread of anatomically modern humans (AMHs). This process of evolution was likely accompanied by global changes in mental and behavioral phenotypes, resulting in cultural differences between AMHs and Neanderthals. Globally, selective increases of frequencies were detected in alleles, which contributed to the suppression of neuroticism and advanced learning. This finding indicates that neuroticism was suppressed and learning behaviors developed through the global spread of AMHs. It suggests that global adaptation to psychosocial stress occurred, which contributed to cumulative cultural evolution by increasing cooperative learning. A comparison of phenotypic trends at the population level indicates that such globally occurring adaptive evolution, entailing neuroticism suppression and increased learning behaviors has been more significant in AMHs than in Neanderthals. However, adaptive evolution toward greater intelligence was more significant in Neanderthals than in AMHs. These findings suggest that mental traits involved in cultural development evolved differently in AMHs and Neanderthals, and that learning behaviors such as cooperative learning, rather than intelligence, played an important role in AMH evolution.

evolutionary biology↗

Lower promoter activity of the ST8SIA2 gene has been favored in evolving human collective brains

ST8SIA2 is the main factor regulating expression of the phenotype involved in schizophrenia. Lowered promoter activity of the ST8SIA2 gene is considered to be protective against schizophrenia by conferring tolerance to psychosocial stress. Here, we examined the promoter type composition of anatomically modern humans (AMHs) and archaic humans (AHs; Neanderthals and Denisovans), and compared the promoter activity at the population level (population promoter activity; PPA) between them. In AMHs, the TCT-type, showing the second lowest promoter activity, was most prevalent in the ancestral population of non-Africans. However, the detection of only the CGT-type from AH samples and recombination tracts in AH sequences showed that the CGT- and TGT-types, exhibiting the two highest promoter activities, were common in AH populations. Furthermore, interspecies gene flow occurred into AMHs from AHs and into Denisovans from Neanderthals, influencing promoter-type compositions independently in both AMHs and AHs. The difference of promoter-type composition makes PPA unique in each population. East and Southeast Asian populations show the lowest PPA. This results from the selective increase of the CGC-type, showing the lowest promoter activity, in these populations. Every non-African population shows significantly lower PPA than African populations, resulting from the TCT-type having the highest prevalence in the ancestral population of non-Africans. In addition, PPA reduction is also found among subpopulations within Africa via a slight increase of the TCT-type. These findings indicate a trend toward lower PPA in the spread of AMHs, interpreted as a continuous adaptation to psychosocial stress arising in migration. This trend is considered as genetic tuning for the evolution of collective brains. The inferred promoter-type composition of AHs differed markedly from that of AMHs, resulting in higher PPA in AHs than in AMHs. This suggests that the trend toward lower PPA is a unique feature in AMH spread.

evolutionary biology↗