Genetic variation and forensic efficiency of 30 indels for three ethnic groups in Guangxi: relationships with other populations.

Weian Du,Hongyan Huang,Ling Chen,Cheng Xiao,Chunlei Feng,Linnan Zhu,Chao Liu,Honghua Qiao,Weibin Wu,Ting Yao

doi:10.7717/peerj.6861

Abstract

AimIn this study, we used a series of diallelic genetic marker insertion/deletion polymorphism (indel) to investigate three populations of Yao, Kelao, and Zhuang groups in the Guangxi region of China and to evaluate their efficiency in forensic application.ResultNo deviations for all 30 loci were observed from the Hardy–Weinberg equilibrium after Bonferroni correction (p > 0.05/30 = 0.0017). The allele frequencies of the short allele (DIP-) for the above three populations were in the range of 0.0520–0.9480, 0.0950–0.8780, and 0.0850–0.915, respectively. The observed heterozygosity of the 30 loci for the three populations was in the ranges 0.0802–0.5802, 0.1908–0.6053, and 0.1400–0.5600, respectively. The cumulative power of exclusion and combined discrimination power for Yao, Kelao, and Zhuang groups were (0.9843 and 0.9999999999433), (0.9972 and 0.9999999999184), and (0.9845 and 0.9999999999608), respectively. The DA distance, principal component analysis, and cluster analysis indicated a clear regional distribution. In addition, Zhuang groups had close genetic relationships with the Yao and Kelao populations in the Guangxi region.ConclusionThis study indicated that the 30 loci were qualified for personal identification; moreover, they could be used as complementary genetic markers for paternity testing in forensic cases for the studied populations.

Highlights

Autosomal short tandem repeat (STR) is a standard marker for DNA analysis in forensic practice
The PE for the 30 indels was less than 0.3 with respect to Yao, Kelao, and Zhuang groups; the PE value was much lower than those of most STRs (Deng et al, 2007; Guo, 2017; Jin et al, 2004). This implies that more loci are needed in indels to achieve the same value of the cumulative power of exclusion (CPE) than that for STR
The above data indicate that polymorphism of indels is lower than STR; this occurs because an indel is a diallele with only two alleles per locus

Summary

Introduction

Autosomal short tandem repeat (STR) is a standard marker for DNA analysis in forensic practice. Compared to the mutation rates of STR (about 10–3), Insertion/deletion polymorphism (indel) markers have significantly lower mutation rates (less than 10–8) (Sobrino & Carracedo, 2005). Single nucleotide polymorphisms (SNPs) have a low mutation rate, it is. Genetic variation and forensic efficiency of 30 indels for three ethnic groups in Guangxi: relationships with other populations. Insertion/deletion polymorphisms are prospective genetic markers and spread widely throughout the genome (Nachman & Crowell, 2000); they combine the desirable characteristics of both STRs and SNPs. Insertion/deletion polymorphism is a length polymorphism marker and it can be analyzed with capillary electrophoresis (Pereira et al, 2009). Indels are considered to be promising markers in forensic application

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Conclusion