Research On Forensic Application Of 20 Microhaplotype Genetic Markers

Objective:In this study,we focused on screening highly polymorphic microhaplotype markers containing tri-allelic SNPs,and evaluating the practical application value of these loci in individual identification,paternity testing,and ancestry inference.Methods:We screened microhaplotype markers containing tri-allelic SNPs and other highly polymorphic microhaplotypes that based on the 1000 Human Genome Project database and next generation sequencing.Then we calculated forensic parameters of microhaplotype markers and explored their applications according to different forensic purposes.Specific primers were designed for each locus,then markers for all samples were sequenced on the Miseq PE300 platform.The sequencing results were used for genetic polymorphisms research.We calculated the forensic genetics parameters through Modified-powerstates.Familias 3software was used to detect parent-child simulation pairs.Finally,STRUCTURE analysis and phylogenetic tree construction were used to analyze the efficiency of ancestry inference.Results:A total of 69 samples were sequenced for 20 microhaplotype loci.According to the screening criteria,the cumulative power of discrimination of the 14 loci used for individual identification was 0.999999999999748.The probability of detecting DNA mixture is 0.9999878.The average A_e value was 3.75.The cumulative exclusion probability CPE_duo and CPE_trio of the 13 paternity testing microhaplotype loci were 0.9931 and 0.9999,respectively.Microhaplotype loci were used for ancestry inference showed genetic differentiation among populations in different regions.According to STRUCTURE analysis,when K=4,it can distinguish the geographical regions of East Asia,South Asia,Africa,and Europe.Conclusion:The microhaplotype genetic marker constructed in this study can be applied for individual identification,ancestry inference and paternity testing.And these markers can enrich the existing microhaplotype genetic marker database.