Human chromosomal polymorphism. IX. Further data on the possible selective value of chromosomal Q-heterochromatin material.

Chromosomal Q-polymorphism was studied in 198 Kirghiz subjects (98 males and 100 females) from one high-altitude isolate located in the south-eastern part of Kirghizia. Small samples of mountaineers (N = 37) and volunteer subjects (N = 34) were also studied. The samples studied did not differ significantly from each other in the relative frequencies of chromosomal variants in 12 loci of seven Q-polymorphic autosomes. The mean number of Q variants per individual in the populations ranged from 1.3 to 2.0. No sex differences were found in the frequencies of Q variants. The observed homo- and heteromorphic frequencies agreed with those predicted by the law of Hardy-Weinberg. The possible selective value of chromosomal Q heterochromatin material in the adaptation of human populations to high-altitude climate is discussed.