Y-Chromosome Heterogeneity in Three Native North American Populations

Ricco, Emily M., Y-chromosome Heterogeneity in Three Native North American Populations. Master of Science (Forensic Genetics), May, 2013, 25 pp., 5 tables, 5 figures, 32 references. Y-chromosome STR haplotype databases for Sioux, native Alaskan, and general Native American populations were used to predict Y-haplogroup designations. A total of 156 Sioux collected from seven geographic regions of South Dakota, 448 native Alaskan collected from three different tribes of Alaska, and 105 undefined Native American YSTR haplotypes were available for analysis. Haplogroups were defined using prediction software that uses a Bayesian model to estimate haplogroup probabilities from STRhaplotype data. The frequency distribution of Y-haplogroups within these Native American populations was calculated from the resulting probabilities to determine the geographical proportions of non-Native American haplogroups. Inter-population heterogeneity was examined with a comparison of contributing haplogroups between the three groups of Native Americans. The results establish the presence of population substructuring within the Native American groups investigated here. This can have implications for the interpretation of Y-STR data in forensic casework, particularly in calculating the rarity of a profile from representative population databases. Accounting for substructuring in genetically heterogeneous populations would facilitate the collection of truly representative samples to be included in forensically relevant databases.