Racial differences in the frequency of Q and C chromosomal heteromorphisms

THE biological and clinical implications of human chromosome heteromorphisms are poorly understood. These heteromorphisms are limited to certain groups, and are heritable¹. Consistent variability between people, in both size and staining properties, is observed. This may reflect either structural or biochemical variations. Before chromosome banding procedures, the length of the Y was known to vary from person to person and from one ethnic group to another². Some autosomal regions were also found to differ in various racial groups^3,4. Using Q- and C-banding procedures, we have regions scored were (1) on the long arms (qh) of chromosomes 1,9 and 16; (2) on the short arms (P) of the acrocentric autosomes (13-15 and 21-22); and (3) on the centromere (c) of all other chromosomes. The results indicate significant differences between the samples of black and white children.