POPULATION GENETIC-CHARACTERISTICS OF THE STR LOCI D21S11 AND FGA IN 8 DIVERSE HUMAN-POPULATIONS

A highly polymorphic multiplex short tandem repeat (STR) system compos ed of D21S11, FGA, and the sex-typing system amelogenin (AMG) has been used to investigate allele frequency distributions in two Canadian Ca ucasian samples (British Columbia and Alberta), three Canadian aborigi nal populations (Coastal Salishans from British Columbia, Ojibwa from northern Ontario, and Cree from Saskatchewan), and three ethnic groups from Singapore (Chinese, Malays, and Asian Indians). Using the automa ted fluorescence detection approach on an ABD 373A DNA Sequencer, we d istinguished 20 D21S11 and 22 FGA alleles with a nearly equal represen tation of two- and four-base variants. An overlap in allele sizes for both STR loci across populations was observed, but frequency differenc es were noted. Statistical analysis revealed that (1) both D21S11 and FGA loci conform to Hardy-Weinberg equilibrium in all eight surveyed p opulations based on five different tests and (2) both STR loci are in linkage equilibrium. Results from the 2 x N contingency table exact te sts for population differentiation demonstrated that the Canadian samp les from two different provinces were not distinguishable from one ano ther at either STR locus and therefore could be combined to form one C aucasian group. Likewise, Chinese and Malays from Singapore did not sh ow significant differences at either STR locus. In contrast, all other examined populations exhibited differences deemed statistically signi ficant. As a complement to our study, we compared D21S11 allele freque ncy distributions in 21 worldwide populations and FGA allele frequency distributions in 14 populations. Many alleles never previously report ed in worldwide populations were identified in Canadian aboriginal and Asian samples from this study. Twenty-four D21S11 and 29 FGA alleles were distinguished in worldwide groups. Interesting similarities in al lele frequency distribution patterns across populations suggest that t he STR polymorphism at these loci predates the geographic dispersal of ancestral human populations. This study further demonstrates the util ity of highly informative STR loci such as D21S11 and FGA in human pop ulation evolutionary history and in forensic medicine.