ИСТИНА

In this study, we employ 35 male cranial samples from North Eurasia, corresponding mtDNA and Y-chromosome samples (from the same populations, not the same individuals), matrices of geographical and climatic distances between the populations in order to systematically assess the influence of the scale of comparison (continental vs. sub-continental vs. regional) on the association between different interpopulation distance matrices. Previous studies have shown that the strength of such association depends on a number of factors: cranial samples and polymorphisms used, part of the skull studied and, importantly, on the scale of comparison (i.e. global, continental, regional or intracemetery). When all studied samples were analyzed together, the craniometric biodistances were equally strongly correlated with genetic and geographic distances (0.60-0.67) while weaker - with climatic distances (0.41). These values are very similar to those published previously for global cranial samples. When sub-continental datasets, i.e. West (20 samples) and East (15 samples) Eurasians, were analyzed separately, correlations with genetic and geographical distances dropped dramatically in both datasets (-0.01-0.45). Simultaneously, ecogeographic correlations increased to reach 0.46 in Europe and 0.53 in Asia which supports previous studies reporting higher association between facial morphology and climate at the continental rather than global scale. Finally, we considered three regional subsets of samples: North Asia (10 populations, cold-adapted), Northeast Europe (10 populations, also cold-adapted) and West and South Europe (10 populations, adapted to temperate or Mediterranean climates). At this scale, all correlations between craniometric distances and genetic, geographic or climatic distances remain low or become even lower than at the sub-continental scale (range from -0.17 to 0.38). One exception is mtDNA distances in North Asia (0.54). Thus at the regional scale, when populations from the same climatic zone are studied, mid-facial craniometric biodistances between the populations remain largely unexplained by either their neutral genetic relationships or climate.