Demography and H-Lea salivary secretion of the Macá Indians of Paraguay

The Macá Indians living at Fray Bartolomé de las Casas show a high rate of endogamy, high mortality (36% of them die before the age of reproduction), low fertility (average of 3.6 livebirths per female who completed her reproductive performance) and low variance in family size. The index of opportunity for selection (0.88) is lower than the one obtained in other populations of agriculturalists and in industrialized communities. The frequency of H secretors (N = 143) is 97% and that of Le^a secretors (N = 123) is 78%.     

Child growth and adult physique in Brazillan Xingu Indians

Data on stature, sitting height, biacromial width, and some other body measurements on 267 children and 363 adults of the Xingu Indians of Brazil have been analyzed. Adult height shows no significant decrease with age over an age range of 20–50 years, thus indicating the absence of secular changes. The average Xingu child seems to be around the twenty-fifth to fiftieth centile for height of British children (if our age estimates are correct) until about ten years in girls and 14 years in boys, but ends at below the third British centile as an adult. In sitting height, however, the Indians show substantially lower values, with children being at about the fifteenth centile until ten years in girls and 14 years in boys, while the adults are considerably below the British third centile. Other comparisons show that the Xingu are taller than Surinam Indians although of similar shoulder width. The lack of anthropometric data concerning South American Indian adults, and more especially children has been stressed. Investigations of these populations facing rapid acculturation and possible assimilation will form a baseline for the future work in public health as contacts with non-Indians increase.     

Genetic demography of the amazonian Ticuna Indians

The Ticuna Indians of Brazil are now a largely acculturated and integrated tribe, situated for the most part in villages along the Solimões river. Demographic information collected in eight of their villages is reported here. For five of them detailed data concerning migration, fertility and mortality were obtained. They are characterized by a relatively large mobility, high fertility (mean number of livebirths per female of age 40 or more: seven), low (2·5%) frequency of sterile couples, and relatively low mortality for groups living at this cultural stage (25% of deaths before the age of reproduction). This low mortality, and a relatively small variance in the number of live-born children in completed families, lead to the lowest index of opportunity for selection obtained thus far in populations of South American Indians (0·54).     

Failure of linguistic relationships to predict genetic distances between the Waiãpi and other tribes of lower Amazonia

Data on blood group, serum protein, erythrocyte enzyme, and histocompatibility antigen (HLA) traits are presented for the Waiãpi, a Tupispeaking tribe of the Brazilian and French Guianas. Intra- and intertribal comparisons have been made between these data, and previously published data from French Guiana, from another Tupi tribe and from other tribes of neighboring areas, and from the continent as a whole. For this purpose, we have modified the usual measure of genetic distance to obtain a value which is independent of the number of loci being considered. The intertribal genetic distances do not correlate with linguistic affinity. Social differences, which may have affected the rate of drift from the continental mean, correlate better with genetic distances.