Distribution of the 9-bp mitochondrial DNA region V deletion among North American Indians

Abstract

The deletion of a 9-bp segment from the intergenic region between the mtDNA cytochrome oxidase II gene and the lysine tRNA gene has been documented mainly in individuals of East Asian ancestry and in individuals from East Asian-derived populations (e.g., Polynesia). Among Native Americans the deletion is absent among Eskimos and northern Na-Dene populations and present among most Amerind populations [sensu Greenberg (1987); i.e., all Native Americans except Eskimo-Aleut and Na-Dene] that have been studied. To better characterize the frequency and distribution of the 9-bp deletion in North America, we surveyed more than 400 individuals from 59 tribes representing a variety of linguistic groups. The absence of the deletion among Eskimo and northern Na-Dene populations is confirmed. Among Amerind groups the deletion is present in all groups represented by more than six individuals. The geographic distribution of the frequencies of the deletion appears to be clinal in North America. The deletion is absent in the Artic and Subartic and reaches its highest frequency in the Southwest. This distribution is consistent with the hypothesis that the ancestors of the Amerinds and Na-Dene arrived in the New World by means of separate migrations. The presence of the 9-bp deletion in high frequencies in all the major linguistic groups in the Southwest suggests that migration among tribes was common.