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Gene flow across tribal barriers and its effect among the Amazonian Içana river Indians
Author(s) -
Salzano F. M.,
Gershowitz H.,
Mohrenweiser H.,
Neel J. V.,
Smouse P. E.,
Mestriner M. A.,
Weimer T. A.,
Franco M. H. L. P.,
Simões A. L.,
Constans J.,
Oliveira A. E.,
de Melo E Freitas M. J.
Publication year - 1986
Publication title -
american journal of physical anthropology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.146
H-Index - 119
eISSN - 1096-8644
pISSN - 0002-9483
DOI - 10.1002/ajpa.1330690103
Subject(s) - inbreeding , demography , gene flow , biology , genetic distance , genetic admixture , founder effect , genetic variation , geography , genetics , population , genotype , gene , haplotype , sociology
Demographic information was obtained from 622 individuals of five communities of primarily Baniwa Amerindians living near the Içana river in Brazil. Four of these populations, plus another from the same area, were also studied genetically. The latter investigation included the blood and, in some cases, saliva of 531 subjects, variously tested in relation to 40 genetic systems. Demographically these groups are characterized by young age, high intertribal admixture, low non‐Indian admixture, high exogamy but low marital distance and high inbreeding, high fertility but low variance in offspring number, and relatively low mortality. Their gene pool shows a peptidase B variant (PEPB 2BAN1 ) and “private” polymorphism of carbonic anhydrase 2 ( CA 2 BAN1 ) until now observed only among them. Other distinctive characteristics are the low frequencies of L NS (0.08), L Ns (0.09), R z (0.01), R O or r (0.02), ACP A (0.08), GALT D (0.01), and the relatively high prevalences of Gm 1;11,13,16 (0.05) and Gc 1 (0.82). T f Dehi occurs with a low prevalence (0.01). Genetic distance analysis reveals that the one Baniwa sample by history comprised of minimally admixed individuals is quite similar genetically to the Wapishana, another Arawak‐speaking tribe some 900 km to the east, and that the genetic distances between the Baniwa communities reflect the amount of historical admixture in a way that indicates which should be excluded from considerations of intertribal genetic distances. Finally, the genetic relation of the Baniwa to the nearby tribes is examined.