The Enhancement of the Native American CODIS STR Database for Use in Forensic Casework

As submitted by the proposer: Population databases on the 13 CODIS STR markers are currently available for only ten Native American tribes, which do not adequately represent the US population diversity. Of the ten tribes, five data sets are derived from Alaska and represent descendants of a small minority of Native American ancestors that arrived long after the initial settlement of the New World and are genetically unrepresentative of most Native Americans living today. No tribes of the American Southwest, Midwest, Southeast, or of Mexico that descended from the initial immigrants to the New World south of Beringia, are represented. The DNA types and allele frequency data from additional tribes would better reflect the population structure among the native groups in the US which in turn would enable more appropriate random match probability estimates to be computed. Therefore, it is essential to develop a more comprehensive STR population database representing geographically and linguistically diverse tribes. Sufficient 'among population' differences exist across tribes to warrant developing a more representative Native American STR database for CODIS. Differences among the CODIS tribes and the vast majority of remaining tribes can be illustrated by their mtDNA haplogroup membership. Native mtDNA is divided into five major haplogroups: A-D and X, which can be further subdivided into 15 subhaplogroups. The mtDNAs comprising the majority of the ten tribes in the CODIS database belong to haplogroups A or D while haplogroups B, C, and X are largely absent. The dearth of population data is especially evident with Native American autosomal STR data, and given that STR typing is the primary analysis system in forensic investigations, population data is critical to reflect multi-tribal genetic composition. Native Americans are unique in that they have the lowest level of heterozygosity yet the highest level of genetic subdivision of any comparable ethnic group worldwide. To develop a more comprehensive Native American database, 100 individuals for each of 13 additional tribal affiliations will be typed across 24 loci, including the original core of 13 autosomal STR loci, which are part of the GlobalFiler Express Kit. The resulting data will be assessed for estimating genetic and geographic substructure and will be formatted using conventional procedures. A comprehensive final report of the studies will be submitted to the funding agency three months prior to the grant's end date. The underlying scientific procedures and results also will be presented to state and federal agencies via forensic meetings and peer-reviewed journals. ca/ncf