Factors in the microevolution of a triracial isolate.

Data on health, morphology, blood types, and hemoglobin types have been presented for two segments of a triracial population isolate in North Carolina. On the basis of blood type gene frequencies, the Indian community is about 18% white, 41% Negro, and 31% Indian, while the non-Indian community is about 35% white, 34% Negro, and 31% Indian. Members of the non-Indian group are slightly more Negroid in appearance, have far more medical problems, and have a slightly lower fertility rate. The development of these two segments of the isolate, similar in most genes but differing in those alleles which permit racial identification, approximated the condition which Stern predicts for Negro-white dynamics of the future. In time, however, political pressures helped to lower barriers to membership in the Indian Association, and in recent years the two segments have become more similar. Migration, differential fertility, and psychology will determine the racial composition of the groups in future years.