Population biology of human aging: segregation analysis of bone age characteristics

The main goal of the present study is to elucidate the extent to which primary characteristics of bone aging are determined by major gene effects. We report the results of a complex segregation analysis of bone mineral density (BMD) and osseographic score (OS) carried out on an array of pedigrees from rural Turkmenia. Both variables showed a significant correlation with age and thus were adjusted. However, the correlations with body height, weight, body mass index, and obesity indexes were negligible. The results of the segregation analysis performed on BMD clearly indicate major gene effects on BMD variation. The Mendelian transmissibility hypothesis with two codominant alleles was chosen as the best-fitting and most parsimonious model. Under this hypothesis 50-60% of total variation in BMD, depending on bone area, can be attributed to a major gene effect, and the frequency of the allele determining the higher value of bone density is between 30% and 38% in the Turkmenian population. Regarding the OS, segregation analysis provided evidence supporting intergenerational transmissibility of this characteristic and yet the Mendelian model was rejected.