ИСТИНА

The question of congruence between genetic and craniometric biodistances in humans is essential for reconstructing relationships between ancient populations or individuals using mor- phometric data. Earlier studies on this issue revealed moderate to high significant correlations between the two types of distances on a global level. Geographical distances are often used as a proxy for genetic distances and show moderate to high correlations with craniometric distanc- es, again on a global level. But later research has shown that those correlations can vary sub- stantially depending 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). The role of climate as an alternative factor shaping the human face has been assessed in numerous studies also showing the fluctuating nature of the association between cranial morphology and climate. We employ 35 male cranial samples from North Eurasia (mid-facial measurements), cor- responding mtDNA and Y-chromosome samples (from the same populations, not the same indi- viduals), and matrices of geographical and climatic distances between the populations in order to systematically assess the influence of the scale of comparison on the association between different interpopulation distance matrices: continental vs. sub-continental vs. regional. At the continental level, when populations from both West and East Eurasia were ana- lyzed together, mid-facial craniometric distances were equally strongly correlated with mtDNA (0.67), Y-chromosome (0.60) and geographical (0.65) distances while a much weaker associa- tion with climatic distances (0.41) was observed. These values are very similar to those pub- lished previously for global cranial samples. When sub-continental datasets, i.e. West (20 samples) and East (15 samples) Eura- sians, were analyzed separately, correlations with genetic and geographical distances dropped dramatically: mtDNA – -0.01 and 0.22; Y-chromosome – 0.42 and 0.45; geographical – 0.32 and 0.20 (Europe and Asia, respectively). Simultaneously, climatic distances became more strongly associated with morphological ones: 0.46 in Europe and 0.53 in Asia. This latter findingFinally, we considered three regional subsets of samples: North Asia (10 populations, all were demonstrated to be cold-adapted), Northeast Europe (10 populations, also all cold-adapted) and West and South Europe (10 populations, adapted to temperate or Mediterranean climates). At this scale, all correlations between craniometric distances and either genetic or geographical 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). But the association with cli- mate is low as well, ranging from 0.05 in Northeast Europe to 0.30 in North Asia. Thus on 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. Certainly, the main explanation of the results of this study seems to be the sampling strategy, where morphological and genetic data are obtained from different individuals. The smaller are the differences between populations (both morphological and genetic), the more important is the effect of sampling. But in our opinion, other important factors are the genetic basis of craniofacial variation and epigenetic effects, internal rather than external, affecting the path from genotype to cranio-facial phenotype.