Major gene control of human body height, weight and BMI in five ethnicallydifferent populations

Pedigree samples were collected from five ethnically and geographically dif ferent populations: Kirghizians, Turkmenians, Chuvashians, Israelis and Mex icans.;lll studied individuals were assessed for body height, weight and BM I. The sample size in the studied pedigrees ranged from 381 to 1811 individ uals. Segregation analysis of these traits preliminarily adjusted for sex a nd age was performed by means of program package MAN that provides paramete r estimates for the major gene effects, for the residual within the genotyp e correlations between relatives and for the assortative mating. By the usu al transmission probability tests: the 'environmental' model was strongly r ejected for all measured traits in all 5 populations. The major gene mode o f inheritance, however, was accepted for all traits. The results of analysi s in 5 populations were remarkably similar, and showed that except for Mexi can sample, the proportion of variance attributable to major gene effect ra nged between 37 and 53% for body weight and height. In the Mexican sample i t explained only about 14% of the body weight variation. The proportion of inter-individual variation in BMI attributable to major gene effect was con sistently lower in all populations in comparison with height and weight and ranged between 17 and 40%. Strong assortive mating in body height, as esti mated by correlation between putative major gene genotypes in spouses, was found in four populations, not including: Mexican pedigrees.