Infracranial versus cranial nonmetric traits and mtDNA data in the study of genetic divergence of human populations

Abstract

AbstractAlthough cranial and dental nonmetric traits have proven to be reliable proxies for genetic data, the usefulness of infracranial nonmetric traits as phenetic markers in population affinity studies remains unclear. Our aim was to analyze infracranial and cranial nonmetric trait frequencies in the same samples in comparison with genetic data to determine the value of infracranial nonmetric traits in assessing genetic relationships among populations. We examined the frequencies of 25 cranial and 16 infracranial nonmetric traits in seven adult osteological samples from different regions of northern Eurasia (northern Russians, indigenous populations of Volga–Ural region, Buryats, and Yupik) and the data on mitochondrial DNA polymorphisms in the same ethnic groups. The biological distance between each pair of samples was estimated using the Smith's mean measure of divergence (MMD) for nonmetric traits and Cavalli–Sforza distance measure for mtDNA data. Mantel correlations were calculated between two matrices of mean measures of divergence (MMD) distances, and a multidimensional scaling (MDS) procedure was applied to each matrix. The Mantel test showed a strong correlation between the two nonmetric distance matrices. The three‐dimensional spatial representations of each matrix revealed similar patterns of intergroup differences. On both nonmetric MDS maps, the sample locations roughly reflected the geographic separation of the groups, with the exception of northern Russians, who were grouped with Volga–Ural populations. Comparison of our results with those obtained from genetic data confirmed that both sets of nonmetric traits provide reliable genetic affinities among the samples. The association of northern Russians with the Volga–Ural groups can be explained by their genetic background. Our findings show that infracranial nonmetric traits can be successfully used as phenetic markers to define a population's affinity and divergence, particularly in cases where only infracranial bones are available for study.