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Population Genetics of SNPs for Forensic Purposes

NCJ Number
Date Published
January 2008
80 pages
The goal of this study was to identify panels of Single Nucleotide Polymorphisms (SNPs) markers with globally low Fst and high average heterozygosity, as well as panels of SNPs markers with globally high Fst and at least moderate average heterozygosity.
The first of these panels would provide exclusion probabilities (or match probabilities) for individual identification with especially low dependence on ancestry. The second panel would provide highly accurate specificity of biological ancestry for forensic investigation. Researchers have produced a large dataset of markers on multiple populations and have found that no obvious algorithm or statistics apparently define a good set of AISNPs (Ancestry Informative SNPs) by statistical criteria researchers are developing. Extensive analyses have begun, but no answers are yet clear. The 40-SNP IISNP panel developed met researchers’ objective in the original application for such a panel of SNPs; however, researchers do not advocate its adoption but do advocate its testing on additional populations and the testing of additional unlinked markers in order to make the panel valid for relationship inference without having to incorporate genetic linkage values into calculation. Efforts to identify AISNPs have shown researchers that the problem is more complex than usually discussed in the literature. Foremost is the fact that markers useful for distinguishing among one specific set of populations is likely to be much less effective in distinguishing among a different set of populations, even if the same geographic regions are involved. Researchers are initially focusing on a panel for robust assignment to four “continental” groups. Progress in this area shows that a small number of AISNPs can do well for assigning individuals from the geographic regions of focus, but does not do well for individuals from intermediate geographic regions. 13 figures, 6 tables, and 39 references

Date Published: January 1, 2008