title: Length heteromorphisms of fluorescent (f) and non-fluorescent (nf) segments of human Y chromosome: classification, frequencies, and incidence in normal Caucasians.
abstract: Sixty normal male Caucasians were selected to study the length of the Y chromosome. QFQ banding was performed. Chromosomes 19 and 20 (F) and Y were measured directly from the film. Y/F, f/F, and nf/F indices (f = fluorescent; nf = non-fluorescent segment) were determined. The length of the Y chromosome was classified into 5 groups; very small, small, average, large, and very large with Y/F indices of less than 0.8, 0.81--0.94, 0.95--1.09, 1.1--1.23, and greater than 1.23, respectively. The frequencies of Y/F indices for these groups were 0 (0%), 9 (15.0%), 40 (66.7%), 8 (13.3%), and 3 (5.0%), respectively. The most frequent class was 0.95--1.09 and was defined as the 'average' Y/F index for the human Y chromosome. The variation in the total length of the Y chromosome was accounted for by variations in the length of the non-fluorescent as well as the fluorescent segments. No relation between f and nf segments was observed. The mean Y/F, f/F, and nf/F indices were 1.022, 0.441, and 0.574, respectively.
mesh_terms: D000328:Adult; D000368:Aged; D002478:Cells, Cultured; D002871:Chromosome Banding; D002903:Chromosomes, Human, 19-20 / Q000648:ultrastructure*; D014644:Genetic Variation; D006801:Humans; D008214:Lymphocytes / Q000648:ultrastructure; D008297:Male; D008875:Middle Aged; D011796:Quinacrine; D012016:Reference Values; D012730:Sex Chromosomes / Q000648:ultrastructure*; D044465:White People; D014998:Y Chromosome / Q000648:ultrastructure*
chemical_list: D011796:Quinacrine