Forensic efficiency estimate and phylogenetic analysis for Chinese Kyrgyz ethnic group revealed by a panel of 21 short tandem repeats.

Yuxin Guo,Bofeng Zhu,Haotian Meng,Wei Cui,Xiaoye Jin,Tong Xie,Chong Chen

doi:10.1098/rsos.172089

Yuxin Guo, Bofeng Zhu + Show 5 more

Open Access

https://doi.org/10.1098/rsos.172089

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Abstract

Short tandem repeats (STRs) with a high level of polymorphisms and convenient detection method play an indispensable role in human population and forensic genetics. Recently, we detected the 21 autosomal non-combined DNA index system (non-CODIS) STR loci in a Kyrgyz ethnic group, calculated their forensic parameters and analysed its genetic relationships with reference populations from China. In total, 168 alleles were observed at 21 non-CODIS STRs with corresponding allelic frequencies from 0.0016 to 0.4788. No significant deviations at these STRs were observed from the Hardy–Weinberg equilibrium. The values of cumulative power of discrimination and probability of exclusion for all the 21 non-CODIS STRs were 0.99999999999999999998835 and 0.9999994002, respectively. Furthermore, the analyses of phylogenetic trees, genetic distances and interpopulation differentiations demonstrated that the Kyrgyz group had relatively close genetic relationships with the Uygur and Kazak groups. These 21 non-CODIS STRs were characterized by high genetic diversities in the Kyrgyz group and could be applied as a robust tool for individual identification and kinship testing in forensic sciences.

Highlights

Short tandem repeats (STRs), as the most common genetic markers, well widespread in the human genome, have had a broad range of applications in DNA profiling of routine casework for several decades [1,2,3,4]
Allelic frequencies and forensic parameters of the 21 non-combined DNA index system (CODIS) STR loci are listed in tables 1 and 2, respectively
The results mentioned above indicated that the panel of non-CODIS 21 STR loci could be used as a sensitive and accurate tool in routine forensic caseworks of the studied Kyrgyz group

Summary

Introduction

Short tandem repeats (STRs), as the most common genetic markers, well widespread in the human genome, have had a broad range of applications in DNA profiling of routine casework (especially in individual identification and paternity testing) for several decades [1,2,3,4]. Many commercial kits of autosomal STRs have been developed [5,6,7], most of them contain the 13 overlapping loci researched by the combined DNA index system (CODIS) [8]. In forensic practice, to solve some disputed kinship testing, such as the duo parentage analysis which lacked the sample from father or mother, usually needs more non-CODIS STR loci to achieve the identifying criterion. The mutation rates of STR loci are relatively high; for this reason, the result of parentage testing tends to be complex if even one or two mismatches occur between parent and offspring. More non-CODIS STR loci are needed as a supplementary. It is meaningful to select more STR loci without the overlapping 13 CODIS core loci in the forensic applications, especially in the complicated kinship cases and missing person investigations

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