[Forensic performance and genetic background analyses of Guizhou Chuanqing population using a self-constructed microhaplotype panel]

Abstract

Objectives: To investigate the ethnic origin of Chuanqing people, one of the largest unidentified ethnic groups in Guizhou, China, and analyze its genetic relationships with surrounding populations.

Methods: Based on a self-developed microhaplotype system, we conducted genotyping and analyzed the genetic distribution of microhaplotype loci and their forensic applicability in Chuanqing population in Guizhou Province. Using the microhaplotype data from different intercontinental populations and previously reported data from Han population living in Guizhou Province, we systematically investigated the genetic background of Chuanqing people through population genetic approaches, including genetic distance estimation, principal component analysis, and phylogenetic tree construction.

Results: Among the studied population, the number of haplotype per microhaplotype ranged from 6 to 25. The average expected heterozygosity (He), observed heterozygosity (Ho), power of discrimination (PD), and probability of exclusion (PE) were 0.8291, 0.8301, 0.9387, and 0.6593, respectively. The cumulative power of discrimination (CPD) and cumulative probability of exclusion (CPE) for these 33 loci were 1-2.62×10^-41 and 1-7.64×10^-17, respectively. Population genetic analyses revealed that the Chuanqing population had close genetic relationships with the East Asian populations, especially the local Guizhou Han population, Beijing Han population and the Han populations living in southern China.

Conclusions: The 33 microhaplotypes exhibit high levels of genetic diversity in the Guizhou Chuanqing population, highlighting their potentials for both forensic identification and parentage testing. The Han populations might have contributed a significant amount of genetic material to the Chuanqing population during the formation and development of the latter.

Keywords: Chuanqing population; forensic performance; genetic structure; microhaplotype.

图1

33个微单倍型位点在贵州穿青人群中的单倍型频率分布 Fig.1 Haplotype frequencies of 33 microhaplotype loci in Guizhou Chuanqing population.

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33个微单倍型位点在贵州穿青人群中的法医学参数 Fig.2 Forensic parameters of 33 microhaplotype loci in Guizhou Chuanqing population.

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贵州穿青人与参考群体的遗传距离热图 Fig.3 Heatmap of genetic distance metrics: Fst (A) and D_A (B) between Guizhou Chuanqing population and the reference groups.

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贵州穿青人与参考群体的主成分分析 Fig.4 Principal component analysis of Guizhou Chuanqing population and the reference groups.

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贵州穿青人与参考群体的多维尺度分析 Fig.5 Multidimensional scaling analysis of Chuanqing people and the reference populations.

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贵州穿青人与参考人群的系统发育树 Fig.6 Neighbor-joining phylogenetic tree between the Chuanqing population and the reference groups.

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穿青人与参考群体的遗传结构分析 Fig.7 Genetic structure analysis of Chuanqing and the reference populations. A: Population genetic structure under different K values. B: Mean LnP(K) values across different K values. C: Genetic component dissection of Chuanqing and the reference populations at K=4.