Autosomal ancestry and male founder events explain variation in male height across 60 Caucasian populations.

backgroundModern genome-wide association studies (GWAS) have shown that research into the genetic determinants of human height is complicated by the highly polygenic nature of height and the strong role of environmental confounders at the individual level. The purpose of the current article was to provide an ecological (country-level) alternative to these studies and to examine geographical associations of genetic factors (25 Y haplogroups, 15 autosomal ancestry components) with the current height of young men in 60 genetically interconnected Caucasian populations of Europe, the Near East, and North Africa.

resultsThis ecological analysis shows that Y haplogroups or their combinations often match almost perfectly the geographical occurrence of a particular autosomal ancestry (correlation coefficients reaching up to r = 0.99), demonstrating that male founder events played a crucial role in shaping population history. Male height adjusted for the main environmental factors (nutrition, child mortality, total fertility) is positively correlated mainly with the Western Balkan Y haplogroup I2a-P37.2, which is associated with local Paleo-Balkan ancestry formed during the Bronze Age. Five other Y haplogroups typical of Northern and Northeastern Europe (I1, N, Q, R1a, R1b-U106) also predict above-average statures. These six Y haplogroups are historically connected with the major European ancestry components Villabruna or Yamnaya, which emerge as the most significant predictors of tallness at the autosomal level. On the other hand, height has the most negative relationship with the three Y haplogroups typical of contemporary Arab populations (E1b-M123, J1, T) and with their autosomal counterpart, the Natufian component of the prehistoric Levant. Of further note is the fact that country-level relationships between height and ancestry components show both concordance and irreconcilable discrepancies with genetic studies using individual-level relationships.

conclusionsThis study provides many compelling results regarding the relationship between male founder events and height, the causality of which can often be supported by already documented findings. Others offer hypotheses that could be tested by more sophisticated research. The incompatibility of some individual-level and country-level data points to the existence of biases in the genetic research of human height in Europe resulting from a one-sided focus on Western European populations.