Gene-culture coevolution in South Amerindians as seen by an individualistic-collectivistic approach

BISSO-MACHADO, R; RAMALLO V; SALZANO FM; HUNEMEIER, T.; BORTOLINI MC

Foz de Iguaçu, PR, Brasil

Congreso; 58° Congresso Brasileiro de Genética; 2012

Sociedade Brasileira de Genética

Human culture has been considered as a powerful factor related to human genetic diversity. Studies have shown thatour adaptive value is influenced by cultural evolution and that the latter occurs much faster than the biological one,generating new selective pressures on the genome based on eventually each migration event and/or change in culturalpractice. The different cultures around the world can be dialectically distinguished as predominantly individualistic ormore collectivistic. Some recent studies (Chiao, J. Y. & Blizinsky, K. D., Proc. Royal Soc. B 277:529-537, 2010) haveassociated these two general cultural aspects to the frequencies of a serotonin transporter functional polymorphism(5-HTTLPR). This gene has two alleles, one long (L) and another small (S), and the small one was reported as morefrequent in collectivistic cultures. The study summarized here aimed to check this relationship in South Amerindianpopulations. A total of 157 individuals from 17 populations were genotyped for the 5-HTTLPR alleles. We assumedthat agriculturalists, who are assembled in larger groups, could be classified as individualists, while hunter-gatherers,with a smaller and more compact structure, could be characterized as collectivists. Of course, this dichotomy isrelative; generally all relatively isolated ethnic groups underwent a transition from hunter-gathering to agriculture,but this varied in time depth and reversals also occurred. With these limitations in mind, we classified the groupsstudied as follows: (a) agriculturalists (individualists): Guarani, n = 24; Lengua, n = 12; Quechua, n = 37; Tenharim,n =1; Total = 74; and (b) hunter-gatherers (collectivists): Apalaí, n = 33; Arara, n= 6; Araweté, n = 2; Gavião, n = 8;Jamamadi, n = 2; Karitiana, n = 3; Kuben-Kran-Kegn, n = 1; Parakanã, n = 1; Suruí, n = 6; Wai-Wai, n = 8; Xavante,n = 5; Xikrin, n =2; Zoró, n = 6; Total = 83. The individualistic group showed an S allele frequency of 0.743, while thecollectivistic group presented a frequency of 0.795. A chi-square test indicated that these two values are statisticallynonsignificantly different [chi-square = 1.194; GL = 1; p = 0.2745; with Yates’ correction (0.918); p = 0.3379]. Thepostulated association therefore, was not confirmed. Behavioral typologies like the one suggested by Chiao and Blizinskyare always a simplification of complex phenomena and should be regarded with caution. But additional Amerindianstudies are necessary to verify if the lack of association obtained here is confirmed. Our results are a reminder thata real process of gene-culture coevolution demands data coming from different geographical areas that need to beconsistent. It is expected that cultural evolution will be more and more present in future studies of human evolution