Gm and Inv allotypes of Brazilian Cayapo Indians.

Abstract

Data from 440 individuals belonging to four populations of Brazilian Cayapo Indians are reported. About 99% of them are Gm (1, 21) or Gm (1, 2, 21), while the frequency of sera with Inv (1) varies from 59%7 to 75%. These values are generally in accordance with those previously obtained among other South American Indians. The four populations can be separated into two groups if the distribution of Gm' 21 and Gm 2, 21 is considered, but this distinction is not apparent in the frequencies of Inv'. A surprisingly high number of samples showed antibody activity against the sensitized red cells, the total frequency of agglutinators being as high as 26%. It is suggested that the prevalence of anti-human globulins should be studied in other populations living at this stage of cultural development.