During the construction of an annotated short tandem repeat (STR) physical map of the human Y chromosome, the authors identified a novel tetra-local locus, DYS503; the current study collected population data from male Caucasian-Americans (n = 980) and African-Americans (n = 100) in order to determine whether DYS503 exhibits an elevated diversity.
Thirty-three unique expanded genotypes were observed among the 198 male samples used in this study. The overall genotype diversity was determined to be 0.92 for the Caucasian-American population and 0.75 for the African-American population. Significant differences in the essentially bimodal genotype distributions were observed between the two populations. The most frequent genotype in Caucasian-Americans was 11-14-14-15 (20 percent of samples); whereas, 13-13-14-14 was the most common genotype observed in the African-American population (49 percent of samples). These findings further showed the significant stratification of the two populations obtained by DYS503 typing. Genotype diversity was higher in Caucasian-Americans (0.92) than in African-Americans (0.75). Population samples for gene-diversity studies were obtained from the Virginia Division of Forensic Science (blood stains). Procedures used in the testing are described. A table presents the genotype frequencies for DYS503 (expanded data) in the two populations, and another table presents allele sequences for DYS503. The complete dataset is available upon request. 2 tables and 5 references