Genetic structure and forensic characterization of 36 Y-chromosomal STR loci in Tibeto-Burman-speaking Yi population

Genetic polymorphism analysis and forensic application evaluation of 57 insertion/deletion polymorphisms from Yi ethnic group in Yunnan

BACKGROUND

As a new kind of diallelic genetic marker, insertion/deletion (InDel) polymorphisms have recently been used in forensic science. However, there are relatively few studies on the forensic evaluation of InDel genetic polymorphisms from different populations.

AIM

The aim of the present work is to assess the genetic polymorphism and forensic applicability of 57 InDels from the Yi ethnic group and explore the genetic background of this group.

SUBJECTS AND METHODS

A total sample of 122 unrelated individuals of Yi group from the Yunnan province were genotyped by the AGCU indel 60 Kit. Multiplex population genetic analyses on the same 57 InDels were carried out among the Yunnan Yi group and 29 reference populations.

RESULTS

The average allele frequency of these loci in the Yi ethnic group was 0.485. Heterozygosity, polymorphism information content, and the power of discrimination were 0.477, 0.362, and 0.612, respectively. The combined power of discrimination and the combined power of exclusion reached to 0.99999999999999999669 and 0.999962965, respectively. The results showed that 57 InDels polymorphisms have high genetic polymorphisms in the Yi ethnic group.

CONCLUSIONS

The 57 InDels could be used for forensic individual identification, paternity testing, and intercontinental population discrimination, with the potential for use in biogeographic ancestry inference.

Genomic formation of Tibeto-Burman speaking populations in Guizhou, Southwest China

Sino-Tibetan is the most prominent language family in East Asia. Previous genetic studies mainly focused on the Tibetan and Han Chinese populations. However, due to the sparse sampling, the genetic structure and admixture history of Tibeto-Burman-speaking populations in the low-altitude region of Southwest China still need to be clarified. We collected DNA from 157 individuals from four Tibeto-Burman-speaking groups from the Guizhou province in Southwest China. We genotyped the samples at about 700,000 genome-wide single nucleotide polymorphisms. Our results indicate that the genetic variation of the four Tibeto-Burman-speaking groups in Guizhou is at the intermediate position in the modern Tibetan-Tai-Kadai/Austronesian genetic cline. This suggests that the formation of Tibetan-Burman groups involved a large-scale gene flow from lowland southern Chinese. The southern ancestry could be further modelled as deriving from Vietnam's Late Neolithic-related inland Southeast Asia agricultural populations and Taiwan's Iron Age-related coastal rice-farming populations. Compared to the Tibeto-Burman speakers in the Tibetan-Yi Corridor reported previously, the Tibeto-Burman groups in the Guizhou region received additional gene flow from the southeast coastal area of China. We show a difference between the genetic profiles of the Tibeto-Burman speakers of the Tibetan-Yi Corridor and the Guizhou province. Vast mountain ranges and rivers in Southwest China may have decelerated the westward expansion of the southeast coastal East Asians. Our results demonstrate the complex genetic profile in the Guizhou region in Southwest China and support the multiple waves of human migration in the southern area of East Asia.

Comprehensive analyses of genetic diversities and population structure of the Guizhou Dong group based on 44 Y-markers

Background

The non-recombining region of the human Y chromosome (NRY) is a strictly paternally inherited genetic marker and the best material to trace the paternal lineages of populations. Y chromosomal short tandem repeat (Y-STR) is characterized by high polymorphism and paternal inheritance pattern, so it has been widely used in forensic medicine and population genetic research. This study aims to understand the genetic distribution of Y-STRs in the Guizhou Dong population, provide reference data for forensic application, and explore the phylogenetic relationships between the Guizhou Dong population and other comparison populations.

Methods

Based on the allele profile of 44 Y-markers in the Guizhou Dong group, we estimate their allele frequencies and haplotype frequencies. In addition, we also compare the forensic application efficiency of different Y-STR sets in the Guizhou Dong group. Finally, genetic relationships among Guizhou Dong and other reference populations are dissected by the multi-dimensional scaling and the phylogenetic tree.

Results

A total of 393 alleles are observed in 312 Guizhou Dong individuals for these Y-markers, with allele frequencies ranging from 0.0032 to 0.9679. The haplotype diversity and discriminatory capacity for these Y-markers in the Guizhou Dong population are 0.99984 and 0.97440, respectively. The population genetic analyses of the Guizhou Dong group and other reference populations show that the Guizhou Dong group has the closest genetic relationship with the Hunan Dong population, and followed by the Guizhou Tujia population.

Conclusions

In conclusion, these 44 Y-markers can be used as an effective tool for male differentiation in the Guizhou Dong group. The haplotype data in this study not only enrich the Y-STR data of different ethnic groups in China, but also have important significance for population genetics and forensic research.

Genetic polymorphisms and phylogenetic characteristics of Tibeto-Burman-speaking Lahu population from southwest China based on 41 Y-STR loci

BACKGROUND

Male sex-linked Y-chromosome short tandem repeats (Y-STRs) have been widely used in forensic cases and population genetics research. At present, the forensic-related Y-STR data in the Chinese Lahu population are still poorly understood.

AIM

To enrich the available Y-STR data of this Chinese minority population and investigate its phylogenetic relationships with other reported populations.

SUBJECTS AND METHODS

The genetic polymorphisms of 41 Y-STR loci were analysed in 299 unrelated healthy Lahu male individuals from Southwest China. Phylogenetic analyses were performed by multidimensional scaling analysis and neighbor-joining phylogenetic tree construction.

RESULTS

A total of 379 alleles were observed at the 41 Y-STR loci. The allele frequencies ranged from 0.0033 to 0.9666. The genetic diversity values ranged from 0.0653 to 0.9072. A total of 254 different haplotypes of the 41 Y-STR loci were observed in 299 individuals. The values of haplotype diversity, haplotype match probability, and discrimination capacity were 0.9987, 0.0047, and 0.8495, respectively. The phylogenetic analysis indicated that the Tibeto-Burman-speaking Lahu population showed a close genetic relationship with the Yunnan Yi population.

CONCLUSIONS

The haplotype data of the present study can enrich the forensic databases of this Chinese minority population and will be useful for population genetics and forensic DNA application.

Genetic characteristics and forensic features of Xibe ethnic group revealed via extended set of Y-STRs

BACKGROUND

Xibe is the fifth largest minority population of Liaoning province. Predominately they live in Liaoning province (69.52%), followed by Xinjiang (18.06%), Heilongjiang (3.99%), Jilin (1.63%) and Inner Mongolia provinces (1.57%).

AIM

To provide an updated and precise population database on an extended set of Y STRs not available before and explore the forensic characteristics of 26 Y chromosomal STRs.

SUBJECTS & METHODS

In this study, we genotyped 406 unrelated Xibe male individuals from Liaoning province using Goldeneye® 26Y System kit and calculated the forensic parameters of these 26 Y STRs loci.

RESULTS

All haplotypes generated for 406 Xibe samples using Goldeneye^® 26Y kit were unique with a discrimination capacity (DC) of 1. On restricting the haplotypes to the Y-filer® set of 17 Y-STRs, we observed 392 haplotypes. Among them 93.53% (380) were unique with a DC of 0.9655 and haplotype diversity (HD) of 0.9998, showing high discrimination power of the extended set of markers in this population. Allelic frequencies ranged from 0.0024 to 0.7684 across 26 Y STRs loci. DYS385 showed the highest gene diversity (0.9691) among all markers.

CONCLUSION

According to pairwise R_ST genetic distances among Xibe populations from China, the Liaoning Xibe population showed the closest genetic distance (0.0035) followed by Xinjiang Xibe population (0.0218). Multidimensional scaling (MDS) analysis among Xibe and 29 other Chinese populations showed that local populations such as Manchu from Liaoning and Han from Beijing had a close affinity while Tibetans from Aba, China, were most distant from Xibe populations. Moreover, 12 individuals showed a null allele at DYS448 in Xibe population samples. We submitted Y-STRs data in the Y-Chromosome Haplotype Reference Database (YHRD) for future forensic and other usage.