The Evolutionary Relationships of Two Populations: A Study of the Guaymi and the Yanomama [and Comments and Reply]

A multidisciplinary study of the Guaymi of western Panama was undertaken to confirm or disprove their apparent similarity to the Yanomama of southern Venezuela and northern Brazil, inferred from allele frequencies for six polymorphic loci studied in the Guaymi by Matson and colleagues in 1965. Gene frequencies were estimated from the present sample of 484, which is more than twice as large as the previous sample and appears to be completely independent of the latter. The findings replicate the gene frequencies obtained earlier, within the terror of resampling after a decade. Leukocytes were typed for A and B locus specificities of the HLA system in 22 Guaymi. A specificity (HLA Bw15) absent from the Yanomama is present in high frequency in the Guaymi. Elsewhere we have reported that a polymorphism of serum albumin in the Yanomama is not present in the Guaymi but that the Guaymi possess polymorphisms of acid phosphatase and lactate dehydrogenase not present in the Yanomama. These findings make any close evolutionary relationship between the two tribes unlikely. Anthropometric data, though not extensive for other tribes, support the conclusion reached from gene frequencies. Of four tribes for which comparable measurements are available, three are more similar to the Guaymi than are the Yanomama, as judged by Mahalanobis's distance. Linguistic studies suggest that the Yanomama language (lexicon) has a larger fraction of cognates with Guaymi than does any other language compared here; however, two other languages in the series (Cashinahua and Shipibo) have higher cognate density with Yanomama than does Guaymi.