title: Human chromosomal polymorphism. V. Chromosomal Q polymorphism in African populations.
abstract: The distribution pattern of Q-heterochromatin variants in seven autosomes (3, 4, 13-15, 21, and 22) was studied in three aboriginal Negroid populations of Africa (Mozambique, Angola, and Ethiopia). It was shown that among African Negroids there are no individuals completely lacking Q-heterochromatin bands with fluorescence levels 4 and 5. The mean number of Q variants per individual was 3.47, 4.80, and 4.85 in the Ethiopian, Mozambique, and Angola populations, respectively. The observed homo- and heteromorphic frequencies always agreed with those predicted by the law of Hardy-Weinberg. The populations of tropical lowland Negroids (Mozambique and Angola) proved to be significantly homogeneous both in the frequency of Q variants and the mean number of these variants per individual, so they were examined as a single group. However, comparative analysis of highland (Ethiopians) and lowland Negroids revealed statistically significant differences. The following questions are discussed: (1) the possible selective value of chromosomal Q heterochromatin material in the adaptation of human populations to high-altitude climate; (2) the possible existence of intraracial heterogeneity in Negroids living in different ecological zones of Africa; (3) the possible taxonomic value of an inverted Q-heterochromatin band in chromosome 3 in ethnic anthropology.
mesh_terms: D000293:Adolescent; D000328:Adult; D000810:Angola; D002871:Chromosome Banding; D002877:Chromosomes, Human; D002900:Chromosomes, Human, 1-3; D002901:Chromosomes, Human, 13-15; D002904:Chromosomes, Human, 21-22 and Y; D002905:Chromosomes, Human, 4-5; D005002:Ethiopia; D006801:Humans; D008297:Male; D009073:Mozambique; D011110:Polymorphism, Genetic