Heritability estimation of 2D:4D finger ratio in a Chuvashian population-based sample

The purpose of this study was to evaluate the familial correlations and heritability of 2D:4D ratio traits using a large population-based sample of ethnically homogeneous pedigrees from Chuvasha and Bashkortostan Autonomies of the Russian Federation.

We calculated the familial correlations and performed a heritability analysis of 2D:4D ratio traits in a sample of 1541 subjects (803 men and 738 women, mean age 47.78 ± 16.89 years, range 18-90 years).

Familial correlations of 2D:4D ratio traits showed no significant correlation for spouses; however, parent-offspring (0.15-0.28, P < .001) and sibling correlations (0.13-0.38, P < .009) were found to be significant. Heritability (H² ) of visual classification of 2D:4D ratio was 0.36 for the left and 0.28 for the right hand; finger ratio was 0.55 and 0.66, respectively; the ray ratio was 0.49 and 0.59, respectively, thus indicating the existence of a clear familial aggregation of 2D:4D ratio variation in the Chuvashian pedigrees, which cannot be explained only by common environmental effects.

Results of our study suggest familial aggregations of finger ratio variation (for all traits) in Chuvashian pedigrees. No evidence of assortative mating was found.