Genetic variation in North Amerindian populations: covariance with climate

Allelic frequencies at seven polymorphic loci in 74 North Amerindian populations are examined relative to patterns of climatic variation. Canonical correlation analysis reveals strong and significant associations of heterozygosity at the ABO, Ss, Duffy, and P loci with climatic variability. Principal component analysis demonstrates that these loci tend to form correlated ensembles. Moreover, canonical correlation analysis of component scores provides support for an association between polymorphism at these loci and environmental variability. The results are concordant with two previous investigations which suggested a relationship between polymorphism for the ABO, Duffy, and Diego systems and climate. It is suggested that the examination of broad geographic patterns of genetic variation at multiple loci is a valuable, but underutilized, method of screening for the effects of long-term systematic pressures.