U.S. flag

An official website of the United States government, Department of Justice.

Population Genetics of SNPs for Forensic Purposes (Updated)

NCJ Number
Date Published
November 2011
103 pages
This project's goals were to improve two preliminary panels of SNP markers: SNPs with globally low Fst and high average heterozygosity for use in individual identification and SNPs with globally high Fst and at least moderate average heterozygosity for use in ancestry inference.
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. Using the researchers' previously described efficient strategy for identifying and characterizing SNPs useful for individual identification, they have identified a sufficient number of SNPs for individual identification (IISNPs), using the researchers' unique collection of cell lines on population samples from around the world. The researchers identified and published (Pakstis et al., 2010) a panel of 92 best SNPs studied on 44 population samples from around the world. These SNPs have both low Fst (less than 0.06) and high heterozygosity (greater than 0.4). Of these, 45 SNPs have no genetic linkage and yield average match probabilities of less than 10 to the -17 power in most of the 44 populations and less than 10 to the -15 power in all, including the several small isolated populations. Of the remaining SNPs, most show no significant pairwise linkage disequilibrium. If only 6 SNPs are set aside as "alternatives," the remaining set of 86 IISNPs are statistically independent at the population level and yield match probabilities less than 10 to the - 31 power irrespective of population. The researchers consider the IISNP panel to be final and have made public the list of IISNPs. A second manuscript is being prepared to provide additional analyses. It will note the additional populations that have been studied for many of the specific IISNPs. 2 tables, 7 figures, and 80 references

Date Published: November 1, 2011