IndroductionThe short tandem repeats (STR) are rich source of highly polymorphic markers in the human genome. In this study, we used a commercially available multiplex STR typing kit to study 15 STR systems (D3S1358, THO1, D21S11, D18S51, Penta E, D5S818, D13S317, D7S820, D16S539, CSF1PO, Penta D, vWA, D8S1179, TPOX and FGA,) in the Mongolians population, and estimated the allele and genotype frequencies. These 15 STR loci include 2 new pentanucleotide repeat STR loci, Penta E and Penta D, so are not studied in Mongolians.GoalTo determine allele frequency of STR loci D3S1358, THO1,D21S11, D18S51, D5S818, D13S317, D7S820, D16S539, CSF1PO, vWA, D8S1179, TPOX, FGA Penta E, Penta D in Mongolian population.Materials and MethodsThe liquid blood, blood stain and saliva samples were taken from 165 unrelated individuals from Mongolian. Extraction DNA: Genomic DNA was extracted from whole blood samples by the standard method of phenol-chloroform-isoamyl alcohol and Wizard Genomic DNA Purification kit, Promega Corporation [21], from blood stain and saliva samples QIAamp DNA micro kit, Qiagen [25], AccuPrep Genomic DNA Extration kit, Bioneer, Koreans extraction method respectively.PCR: PCR amplification was performed using 10-15 ng genomic DNA template according to manufacturer’s protocol (PowerPlex® 16 and PowerPlex® 16HS kit, Promega Corporation, USA). Typing: DNA typing was performed on the ABI Prism 310 Genetic Analyzer (Applied Biosystems) using the recommended protocol. The results were analyzed by Data Collection (Version 1.1), GeneScan (Version 3.1), and Genotyper (Version 3.1) softwares (AppliedBiosystems).ResultsWe assessed forensic and population genetic studies using 15 STR loci included in s sample of 165 unrelated individuals from Mongolian. Allele frequency were listed in Table 2. Totally 20 alleles /5, 7-25/ were found from microsatellite Penta E locus and allele 11 has most frequent (0.1128). 6-16 alleles were found from Penta D locus and allele 9 has most frequent (0.3262). This result is interesting because allele 6 of Penta D locus was found rarely among other populations. But relatively higher frequency of allele 6 (0.0183) was found in Mongolian population. A population comparison based in genetic distance and genetic diversity calculated from allele frequencies of the 15 STR loci from obtained five different populations is shown the Table 3. Conclusions:1. Penta E locus was highly polymorphic, and 20 alleles were found in this Mongolians population and allele 11 was most frequent.2. Penta D locus was 20 alleles were found in this Mongolians population and allele 9 was most frequent.