Pedigree samples were collected from five ethnically and geographically
different populations:
Kirghizians, Turkmenians, Chuvashians, Israelis and Mexicans. All studied
individuals were assessed
for body height, weight and BMI. The sample size in the studied pedigrees
ranged from 381 to 1811
individuals. Segregation analysis of these traits preliminarily adjusted
for sex and age was performed
by means of program package MAN that provides parameter estimates for the
major gene effects, for
the residual within the genotype correlations between relatives and for
the assortative mating. By
the usual transmission probability tests, the ‘environmental’
model was strongly rejected for all
measured traits in all 5 populations. The major gene mode of inheritance,
however, was accepted for
all traits. The results of analysis in 5 populations were remarkably similar,
and showed that except
for Mexican sample, the proportion of variance attributable to major gene
effect ranged between 37
and 53% for body weight and height. In the Mexican sample it explained
only about 14% of the
body weight variation. The proportion of inter-individual variation in
BMI attributable to major
gene effect was consistently lower in all populations in comparison with
height and weight and
ranged between 17 and 40%. Strong assortive mating in body height, as estimated
by correlation
between putative major gene genotypes in spouses, was found in four populations,
not including
Mexican pedigrees.