Population-Specific Deviations of Global Human Craniometric Variation From a Neutral Mode

摘要

Past studies have revealed that muchnof human craniometric variation follows a neutralnmodel of population relationships. At the same time,nthere is evidence for the influence of natural selectionnin having shaped some global diversity in craniomet-nrics. In order to partition these effects, and to explorenother potential population-specific influences, this arti-ncle analyzes residuals of craniometric distances from angeographically based neutral model of population struc-nture. W.W. Howells’ global craniometric data set wasnused for these analyses, consisting of 57 measurementsnfor 22 populations around the world, excluding Polyne-nsia and Micronesia because of the relatively recent set-ntlement of these regions. Phenotypic and geographicndistances were derived between all pairs of populations.nThree-dimensional multidimensional scaling configura-ntions were obtained for both distance matrices, andncompared using a Procrustes rotation method to shownwhich populations do not fit the geographic model. Thisnanalysis revealed three major deviations: the Buriat,nGreenland Inuit, and Peru. The deviations of the Buriatnand Greenland Inuit appear to be related to long-termnadaptation to cold environments. The Peruvian samplenis more similar to other New World populations thannexpected based on geographic distance alone. This devi-nation likely reflects the evolutionarily recent movementnof human populations into South America, such thatnthese populations are further from genetic equilibrium.nThis same pattern is seen in South American popula-ntions in a comparative analysis of classical geneticnmarkers, but not in a comparative analysis of STR loci,nperhaps reflecting the higher mutation rate for thenlatter