The authors present a sero-anthropological study of 205 Mapuche Indians from Cautín (Chile). There were 86.8 per cent of group O, 8.3 per cent of subgroup A1, 0.5 per cent of subgroup A2, 3.4 per cent of group B, and 1.0 per cent of subgroup AB.

The 3.4 per cent group B in the series may be due to crossing with whites or to the fact that this group was always present in Mapuches even before contact with whites.

The frequency of the standard Rh factor percentage is very high (98.6 per cent) but not 100 per cent as in the data of North American investigators.


This is the fourth paper in a series on the distribution of blood groups among Indians of South America. It reports the findings on the Indians of Chile and the Polynesians of Chile's Easter Island. Blood specimens were procured from the following putatively pure Indians and unmixed Polynesians: 44 Alacaluf of Puerto Eden, Isla Wellington, 141 Mapuche (Araucanian) of Lonquimay, Malleco Province, 80 Atacameños of Antofagasta Province, and 45 Polynesians of Easter Island. These 310 samples were tested for blood factors in the A-B-O, M-N-S-s, P, Rh-Hr, Lutheran, K-k, Lewis, Duffy, Kidd and Diego systems, and for the Wright (Wra) agglutinogen. Serum samples were tested for haptoglobins and transferrins. Hemolysates prepared from the blood clots were tested for hemoglobin types. The results are presented as phenotype incidences and calculated gene frequencies in appropriate tables. Locations of the populations from which blood samples were procured are shown on two maps.

The high frequencies for the O gene usually reported for South American Indians obtain in putatively pure Chilean Indians but A1 is high in Easter Island Polynesians. In both Indians and Polynesians M, s, R1 (CDe), R2 (cDE), Lub, k, LeH, and Fya gene frequencies are high and B, N, S, Mia, Vw, Rº (cDe), r (cde), Lua, K, Le1, Fyb, and Wra (Ca) are low or absent. The Diego (Di) gene is present in the Mapuche and Atacameños but absent in the Alacaluf and Polynesians.

Hp1 gene frequencies were determined only in the Alacaluf and Atacameños, in which they are 0.48 and 0.67 respectively.

Transferrins were determined for the Alacaluf and Atacameños Indians and all were classified as Tf C.

All Chilean Indian and Polynesian specimens were tested electrophoretically for hemoglobin types and all contained only hemoglobin (A) as a major component.

Source: Distribution of hereditary blood groups among Indians in South America. IV. In Chile with inferences concerning genetic connections between Polynesia and America

In three cities of Chile (Santiago, Valparaiso, Valdivia) the A allele and phenotype (ABO blood group) are more frequent in the higher socioeconomic strata (SES) and the O allele and phenotype are in the lower ones. This constitutes a structured sociogenetic cline (SGC). The B allele and phenotypes (B+AB) present a rather erratic or contradictory distribution among SES. This SGC was also found in England. The standard interpretation of the origin and maintenance of this SGC in Chile is founded on socio-ethno-historic-cultural and drift factors followed by socioeconomic assortative mating that has occurred since the origin of Chileans by the admixture of Europeans and Amerindians. This interpretation is insufficient to explain the coincidence of the cline in England and Chile, and for some findings in Chile. 1) The A and Rh(-) frequencies of the highest SES in Chile are significantly higher than those found in Europeans. 2) The B gene and phenotypes (with AB) behave differently and in contradiction to the socio-ethno-cultural-historical process. 3) There is a significant interaction of the SGC with gender in Chile and England. There is not at present a putative relationship between ABO and psycho-social factors that could account for this sociogenetic interaction. This SGC seems to be present in societies with a hierarchical organization in relation to power, prestige, ownership, income and life style, and when sampling includes the most extreme SES. It has not been found in two samples from Ireland and in a sample from Chile taken from a public hospital, probably because those variables and conditions were not ascertained.



Historical and anthropological data suggest the presence of descendents of Changos, Cuncos, Chonos and Yamanas, South American indian populations, in certain Chilean coastal villages.


To assess the degree of South American indian admixture in Chilean coastal villages using protein markers, to complete the assessment of human biological diversity in Chile.


ABO, Rh, MNS, Duffy and Kidd blood group systems were assessed in 47, 48, 55 and 24 individuals from Paposo, Carelmapu, Laitec and Ukika respectively. Phenotypic and gene frequencies were calculated. The degree of South American indian admixture was estimated from the ABO*O allele and Rh*dce haplotypes.


High frequencies of ABO*O, Fy*a, Jk*b alleles, Dce and Ms haplotypes were found in all villages, consistent with the pattern expected for South American Aboriginal populations. The highest presence of South American indian admixture was present in Laitec with 80% and in Ukika with 74%. The figures for Paposo and Carelmapu were 60 and 65% respectively.


According to South American indian admixture estimates, the genetic isolation of coastal populations is lower than that of inland subjects, suggesting that sea proximity facilitates gene flow.

Source: Coastal Chilean populations: genetic markers in four locations