Genetic diversity, structure and forensic characteristics of Hmong-Mien-speaking Miao revealed by autosomal insertion/deletion markers

Insertion/deletion (Indel) genetic markers have special features compared to other forensic-related markers, such as the low mutation rate and di-allelic markers with length polymorphism, playing an indispensable role in the forensic and population genetics, molecular anthropology and evolutionary biology. However, the genetic diversity, allelic frequency, forensic parameters and population genetic characteristics of the Indel markers in Hmong-Mien-speaking Guizhou Miao people are unclear due to the sparse sampling. Thus, we genotyped 30 forensic-related Indel markers in 311 unrelated healthy Miao individuals (149 females and 161 males) residing in the Guizhou Province in Southwest China using the Investigator DIPplex amplification system. All 30 Indels are in accordance with the no departures of Hardy-Weinberg equilibrium and linkage disequilibrium. The combined probability of discrimination and the probability of exclusion in Guizhou Miao population are 0.999999999948 and 0.9843, respectively. This observed ideal forensic parameter estimates indicate that this di-allelic Indel panel can be used as a supplementary tool in forensic retinue personal identification and complemented for autosomal STRs in the parentage testing in Miao population, especially used as the main tool in old or highly degraded samples in disaster victim identification. Eleven Indels show a high allele frequency difference between different continental populations and could be used as ancestry-informative markers in forensic ancestry inference. Phylogenetic relationships between Guizhou Miao and 68 worldwide populations based on the genetic polymorphisms of Indels are investigated via three different pairwise genetic distances, principal component analysis, multidimensional scaling analysis and phylogenetic relationship reconstructions. Analyses of the comprehensive population genetic relationship comparison reveal significant genetic differentiation of Chinese groups. Our results demonstrate that Guizhou Miao people are genetically closer related to the geographically adjacent populations, especially with Liangshan Yi, Guangxi Miao and Dong, but genetically distinct with Turkic-speaking populations. Comprehensive and precise genetic admixture and divergence history of Guizhou Miao and neighboring populations are needed to further investigate and reconstruct via high-density marker panel or whole-genome sequencing of modern or ancient Miao samples.