[Population genetics study of differential fertility in humans (based on an example of habitual abortion). III. Distribution of individual heterozygosity and genotype combinations for 9 polymorphic loci].

Distribution of individual heterozygosity (the number of heterozygous loci per individual), wife/husband genetical differences and frequencies of genotypes formed by paired combination of eight polymorphic loci were studied in a group of couples and single women with repeated spontaneous abortions, and in a group of couples with normal fertility. No statistically significant differences were found for the first two parameters. Marked increase of genetical variability was shown for the women with repeated spontaneous abortions, as consequence of elevation of frequency of rare genotypic paired combinations. Therefore, differential fertility, as a component of stabilizing selection, alters the distribution of complex genotypes in human populations.