Improving empirical evidence on differentiating closely related men with RM Y-STRs: A comprehensive pedigree study from Pakistan

Improving the strategy to identify historical military remains: a literature review and Y-STR meta-analysis

The identification of historical military remains by Unrecovered War Casualties-Army (UWC-A) currently relies on Y-chromosome Short Tandem Repeat (Y-STR) testing when maternal relatives are not available, or when a mitochondrial DNA match does not provide sufficient certainty of identification. However, common Y-STR profiles (using Yfiler™) between sets of remains or families often prevent identification. To resolve these cases, an investigation of additional Y-DNA markers is needed for their potential inclusion into the DNA identification strategy. The number of genetic transmissions between missing soldiers and their living relatives needs to be considered to avoid false exclusions between paternal relatives. Analysis of 236 World War I/II (WWI/II) era pairs of relatives identified up to seven genetic transmissions between WWII soldiers and their living relatives, and nine for WWI. Previous Y-STR meta-analyses were published approximately 10 years ago when rapidly mutating markers were relatively new. This paper reports a contemporary literature review and meta-analysis of 35 studies (which includes 23 studies not previously used in meta-analysis) and 23 commonly used Y-STR's mutation rates to inform the inclusion of additional loci to UWC-A's DNA identification strategy. Meta-analysis found mutation data for a given Y-STR locus could be pooled between studies and that the mutation rates were significantly different between some loci (at P < 0.05). Based on this meta-analysis, we have identified two additional markers from PowerPlex® Y23 for potential inclusion in UWC-A's identification strategy. Further avenues for potential experimental exploration are discussed.

Key points

From 236 UWC-A pairs of relatives, we observed up to nine genetic transmissions between WWI soldiers and their living relatives, and seven for WWII.MedCalc® software for meta-analysis utilizing the Freeman-Tukey transformation was run, which analysed 35 published studies and 23 commonly used loci. Previous Y-STR mutation rate meta-analyses are now 10 years old; this paper includes 23 studies that were not included in previous meta-analyses.Through meta-analysis, we identify two markers from PowerPlex® Y23 for potential inclusion in UWC-A's historical remains identification strategy (alongside Yfiler™). We discuss potential next steps for experimental exploration of additional Y-DNA markers.

Unraveling the paternal genetic structure and forensic traits of the Hui population in Liaoning Province, China using Y-chromosome analysis

The Hui people are the second-largest ethnic minority in China, and they are distributed throughout the country. A previous study explored the paternal genetic structure of the Hui population in nine different regions of China, but it overlooked the Liaoning province. In this study, we examined the paternal genetic makeup and forensic traits of the Hui population in Liaoning province by analyzing 157 Y-chromosome single nucleotide polymorphisms (Y-SNPs) and 26 short tandem repeats (Y-STRs). We successfully genotyped 282 unrelated male individuals from the Hui population of Liaoning province using the SNaPshot® single base extension assay and Goldeneye™ Y26 system kit (PEOPLESPOT R&D, Beijing, China). The results revealed high haplotypic diversity (0.9998) and identified 46 terminal haplogroups for the Hui population. Additional analyses, such as heat maps, principal component analysis (PCA), genetic distance (FST), Multidimensional scaling (MDS) analysis, and median-joining network (MJ) analysis, showed that the Hui population could be classified into three groups: Northwest Hui populations (NWH), including Liaoning, Xinjiang, Qinghai, Gansu, Ningxia, Shaanxi, and Henan; Hui populations from Sichuan and Shandong (SSH); and Yunnan Hui populations (YNH). Pairwise genetic distance (Rst) comparisons with other Chinese populations revealed that the Hui population displayed genetic affinity with the Han population. The comprehensive understanding of the Hui population in Liaoning province, explored by Y-SNPs and Y-STRs, can be utilized to interpret their genetic structure and enhance the accuracy of forensic databases.

Genetic diversity of 23 Y-STR loci of the Lisu ethnic minority residing in Chuxiong Yi Autonomous Prefecture, Yunnan province, Southwest China

BACKGROUND

The Lisu group is a unique minority in Yunnan province. However, there is a lack of Y-STR population data for Chinese Lisu and the genetic structure of the Lisu group and other populations is unclear.

AIM

To provide genetic data for 23 Y-STRs in the Chinese Lisu population from Chuxiong Yi Autonomous Prefecture, as well as to analyse population genetic relationships between Chinese Lisu ethnic minority and other reference groups.

SUBJECTS AND METHODS

423 unrelated healthy Lisu males were genotyped using the PowerPlex® Y23 system. Forensic parameters were calculated according to the previously published studies. Genetic structure analysis among Chinese Lisu and other populations was conducted using the YHRD's AMOVA tools.

RESULTS

Gene diversity (GD) ranged from 0.2,466 (DYS438) to 0.8,945 (DYS385a/b) among the 23 Y-STR loci. According to haplotype analysis, 323 different haplotypes were obtained, out of which 271 were unique. The haplotype diversity (HD) and discrimination capacity (DC) were 0.9,977 and 0.7,636, respectively. MDS plot indicated that the Chuxiong Lisu group is genetically related to the Yunnan Yi group.

CONCLUSIONS

This is the first report on Y-STR population data for the Chinese Lisu population. These data would be valuable for forensic applications.

Comparison between MACSprep™ forensic sperm microbead kit and Erase Sperm Isolation kit for the enrichment of sperm fractions recovered from sexual assault samples

Sexual assault samples often contain mixtures of cells coming from at least two donors. Ideally, one would need to separate the cells into two cellular fractions: one consisting of the alleged aggressor's spermatozoa (the sperm fraction) and the other containing the victim's epithelial cells (the non-sperm fraction). This separation increases the probability of obtaining the alleged offender's autosomal DNA profile. However, spermatozoa are often collected along with an excess of biological material originating from the victim, and with unfavorable male:female biological material ratios, the absence of separation could result in the PCR amplification of the victim's DNA profile only. Several approaches are available to enrich/purify the spermatozoa present on sexual assault samples. In this paper, we compare a new method, the MACSprep™ Forensic Sperm MicroBead Kit (MACSprep, based on microbeads conjugated with antibodies bound to spermatozoa and their retention within a magnetic column) with the Erase Sperm Isolation Kit (Erase, a standard differential lysis separation procedure combined with a specific removal of free DNA) routinely used in our lab. The performance of both kits was tested using sets of vaginal and buccal swabs loaded with different dilutions of sperm, or azoospermic semen, representing a total of 120 independent samples. For the samples containing undiluted sperm, an average recovery of 58% was observed for the MACSprep's sperm fractions and 43% for Erase's. Significantly better recovery of azoospermic semen was observed in MACSprep's non-sperm fractions (~ 85%) compared to Erase (~ 28%). Erase performed significantly better than MACSprep in terms of recovery for diluted sperm samples (1:10 to 1:800 sperm dilutions) in the presence of vaginal cells, while the purities of the achieved sperm fractions were in favor of MACSprep for the highest sperm dilutions tested. Similar trends were observed with buccal swabs loaded with 1:200 sperm dilutions. Increased sperm dilutions on vaginal swabs resulted in higher variability in the male material recovered, whatever the separation method used. Both methods were easy to perform and resulted in male DNA extracts ready to use in less than 2 h. Both kits showed their specificities in terms of recovery efficiency and purity of the sperm fractions. Ideally, additional experiments should be performed in different laboratories, using workflow and chemistries different than ours, to better define the peculiarities observed with MACSprep for high dilutions. Improving the recovery of MACSprep for diluted samples, in addition to its better purity observed in the experiments performed, could make it a method of choice for laboratory workflow, despite MACSprep's current price per sample being about twice the price of Erase's.

Genetic diversity and forensic application of Y-filer STRs in four major ethnic groups of Pakistan

17 Y-chromosomal STRs which are part of the Yfiler Amplification Kit were investigated in 493 unrelated Pakistani individuals belonging to the Punjabi, Sindhi, Baloch, and Pathan ethnic groups. We have assessed the forensic parameters and population genetic structure for each group. Among the 493 unrelated individuals from four ethnic groups (128 Baloch, 122 Pathan, 108 Punjabi, and 135 Sindhi), 82 haplotypes were observed with haplotype diversity (HD) of 0.9906 in Baloch, 102 haplotypes with HD value of 0.9957 in Pathans, 80 haplotypes with HD value of 0.9924 in Punjabi, and 105 haplotypes with HD value of 0.9945 in the Sindhi population. The overall gene diversity for Baloch, Pathan, Punjabi, and Sindhi populations was 0.6367, 0.6479, 0.6657, and 0.6112, respectively. The results had shown us that Pakistani populations do not have a unique set of genes but share the genetic affinity with regional (Central Asia and Northern India) populations. The observed low gene diversity (heterozygosity) values may be because of endogamy trends and this observation is equally supported by the results of forensic parameters which are mostly static across 4 combinations (minimal STRs, extended 11 Y-STRs, Powerplex 12 Y System, and Yfiler 17 Y-STRs) of STRs in these four populations.

Genetic admixture history and forensic characteristics of Tibeto-Burman-speaking Qiang people explored via the newly developed Y-STR panel and genome-wide SNP data

Fine-scale patterns of population genetic structure and diversity of ethnolinguistically diverse populations are important for biogeographical ancestry inference, kinship testing, and development and validation of new kits focused on forensic personal identification. Analyses focused on forensic markers and genome-wide single nucleotide polymorphism (SNP) data can provide new insights into the origin, admixture processes, and forensic characteristics of targeted populations. Qiang people had a large sample size among Tibeto-Burmanspeaking populations, which widely resided in the middle latitude of the Tibetan Plateau. However, their genetic structure and forensic features have remained uncharacterized because of the paucity of comprehensive genetic analyses. Here, we first developed and validated the forensic performance of the AGCU-Y30 Y-short tandem repeats (STR) panel, which contains slowly and moderately mutating Y-STRs, and then we conducted comprehensive population genetic analyses based on Y-STRs and genome-wide SNPs to explore the admixture history of Qiang people and their neighbors. The validated results of this panel showed that the new Y-STR kit was sensitive and robust enough for forensic applications. Haplotype diversity (HD) ranging from 0.9932 to 0.9996 and allelic frequencies ranging from 0.001946 to 0.8326 in 514 Qiang people demonstrated that all included markers were highly polymorphic in Tibeto-Burman people. Population genetic analyses based on Y-STRs [RST, FST, multidimensional scaling (MDS) analysis, neighboring-joining (NJ) tree, principal component analysis (PCA), and median-joining network (MJN)] revealed that the Qiang people harbored a paternally close relationship with lowland Tibetan-Yi corridor populations. Furthermore, we conducted a comprehensive population admixture analysis among modern and ancient Eurasian populations based on genome-wide shared SNPs. We found that the Qiang people were a genetically admixed population and showed closest relationship with Tibetan and Neolithic Yellow River farmers. Admixture modeling showed that Qiang people shared the primary ancestry related to Tibetan, supporting the hypothesis of common origin between Tibetan and Qiang people from North China.

Mutation analysis for newly suggested 30 Y-STR loci with high mutation rates in Chinese father-son pairs

Rapidly mutating Y-STRs (RM Y-STRs) harbor great potential to distinguish male relatives and achieve male identification. However, forensic applications were greatly limited by the small number of the initially identified 14 RM Y-STRs. Recently, with the emergence of 12 novel RM Y-STRs, an integrated panel named RMplex was introduced, which contains all 26 RM Y-STRs and four fast mutating Y-STRs (FM Y-STRs). To obtain the first data on the mutation rates and father-son differentiation rates of the 30 newly proposed Y-STRs in Chinese populations, we performed an empirical mutation study on 307 DNA-confirmed Chinese paternal pairs. Previously reported mutation rates for 14 RM Y-STRs in Chinese and European populations were pooled and merged with our data. The highest meiosis number for the two groups reached 4771 and 2687, respectively. Five loci showed significant differences between the populations (DYS570, DYS399S1, DYS547, DYS612, and DYF403S1b). For the new panel covering 30 Y-STR loci, our results show extensive differences in the mutation rates between the two populations, as well. 10 RM Y-STR loci showed relatively low mutation rates (10^-3-10^-2 per meiosis) and 2 FM Y-STR loci had rapid mutation rates (> 10^-2 per meiosis) in the Chinese population. Several-fold differences in mutation rates were found in nine Y-STR loci between the Chinese and reference populations, with two loci having significantly higher mutation rates and one locus with a significantly lower mutation rate in the Chinese population (P < 0.05). Eighteen RM Y-STRs (> 10^-2 per meiosis), 8 FM Y-STR loci (5×10^-3-10^-2 per meiosis), 3 moderately mutating Y-STRs (MM Y-STRs, 10^-3-5×10^-3 per meiosis), and one locus with no observed mutation events were identified in the Chinese population. 40.06% of the Chinese paternity pairs were discriminated with RMplex while only 20.84% with the initial 14 RM Y-STRs, indicating that RMplex is beneficial for distinguishing paternally related males. Future studies on populations of different genetic backgrounds are necessary to obtain comprehensive estimates of mutation rates at these new loci.

Genetic polymorphism and forensic application of 23 autosomal STR loci in the Han population of Panjin City, Liaoning Province, Northeastern China

BACKGROUND

Short tandem repeats (STRs) are consecutive repetition of a repeat motif and widely used in forensic medicine and human genetics because of their high polymorphism.

SUBJECTS AND METHODS

In the current study, 23 autosomal STR loci were genotyped from 1263 unrelated healthy individuals living in Panjin City, Liaoning Province, Northeastern China using the VeriFiler^TM Express PCR Amplification Kit. The population comparison was performed between the Panjin Han population and the other relevant groups to further explore the structure of Panjin Han and its relationship with the other groups.

RESULTS

The results found 316 alleles across the 23 STRs and the corresponding allelic frequencies ranged from 0.5198 to 0.0004. Except for D3S1358, TPOX, TH01, and D3S1358, all STR loci were highly polymorphic (PIC > 0.7), with the Penta E locus having the highest degree of polymorphism (0.9147). For population comparison, the exact test of population differentiation found that no significant difference was observed between the Panjin Han and the other Han populations, except for Guangdong Han and Jiangxi Han.

CONCLUSION

The Panjin Han population showed significant differences with the other ethnic groups in China (Bouyei, Dong, Hui, Miao, Tibetan, and Uygur) and the foreign ethnic groups.

RMplex reveals population differences in RM Y-STR mutation rates and provides improved father-son differentiation in Japanese

Rapidly mutating Y chromosomal short tandem repeat markers (RM Y-STRs) -characterized by at least one mutation per 100 generations- are suitable for differentiating both related and unrelated males. The recently introduced multiplex method RMplex allows for the efficient analysis of 30 Y-STRs with increased mutation rates, including all 26 currently known RM Y-STRs. While currently available RM Y-STR mutation rates were established mostly from European individuals, here we applied RMplex to DNA samples of 178 genetically confirmed father-son pairs from East Asia. For several Y-STRs, we found significantly higher mutation rates in Japanese compared to previous estimates. The consequent father-son differentiation rate based on RMplex was significantly higher (52%) in Japanese than previously reported for Europeans (42%), and much higher than with Yfiler Plus in both sample sets (14% and 13%, respectively). Further analysis suggests that the higher mutation and relative differentiation rates in Japanese can in part be explained by on average longer Y-STR alleles relative to Europeans. Moreover, we show that the most striking difference, which was found in DYS712, could be linked to a Y-SNP haplogroup (O1b2-P49) that is common in Japanese and rare in other populations. We encourage the forensic Y-STR community to generate more RMplex data from more population samples of sufficiently large sample size in combination with Y-SNP data to further investigate population effects on mutation and relative differentiation rates. Until more RMplex data from more populations become available, caution shall be placed when applying RM Y-STR mutation rate estimates established in one population, such as Europeans, to forensic casework involving male suspects of paternal origin from other populations, such as non-Europeans.

Mutation Rate Analysis of RM Y-STRs in Deep-Rooted Multi-Generational Punjabi Pedigrees from Pakistan

Y chromosome short tandem repeat polymorphisms (Y-STRs) are important in many areas of human genetics. Y chromosomal STRs, being normally utilized in the field of forensics, exhibit low haplotype diversity in consanguineous populations and fail to discriminate among male relatives from the same pedigree. Rapidly mutating Y-STRs (RM Y-STRs) have received much attention in the past decade. These 13 RM Y-STRs have high mutation rates (>10−2) and have considerably higher haplotype diversity and discrimination capacity than conventionally used Y-STRs, showing remarkable power when it comes to differentiation in paternal lineages in endogamous populations. Previously, we analyzed two to four generations of 99 pedigrees with 1568 pairs of men covering one to six meioses from all over Pakistan and 216 male relatives from 18 deep-rooted endogamous Sindhi pedigrees covering one to seven meioses. Here, we present 861 pairs of men from 62 endogamous pedigrees covering one to six meioses from the Punjabi population of Punjab, Pakistan. Mutations were frequently observed at DYF399 and DYF403, while no mutation was observed at DYS526a/b. The rate of differentiation ranged from 29.70% (first meiosis) to 80.95% (fifth meiosis), while overall (first to sixth meiosis) differentiation was 59.46%. Combining previously published data with newly generated data, the overall differentiation rate was 38.79% based on 5176 pairs of men related by 1−20 meioses, while Yfiler differentiation was 9.24% based on 3864 pairs. Using father−son pair data from the present and previous studies, we also provide updated RM Y-STR mutation rates.

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.

Empirical Evidence on Enhanced Mutation Rates of 19 RM-YSTRs for Differentiating Paternal Lineages

Rapidly mutating Y-chromosomal short tandem repeats (RM Y STRs) with mutation rates ≥ 10⁻² per locus per generation are valuable for differentiating amongst male paternal relatives where standard Y STRs with mutation rates of ≤10⁻³ per locus per generation may not. Although the 13 RM Y STRs commonly found in commercial assays provide higher levels of paternal lineage differentiation than conventional Y STRs, there are many male paternal relatives that still cannot be differentiated. This can be improved by increasing the number of Y STRs or choosing those with high mutation rates. We present a RM Y STR multiplex comprising 19 loci with high mutation rates and its developmental validation (repeatability, sensitivity and male specificity). The multiplex was found to be robust, reproducible, specific and sensitive enough to generate DNA profiles from samples with inhibitors. It was also able to detect all contributor alleles of mixtures in ratios up to 9:1. We provide preliminary evidence for the ability of the multiplex to discriminate between male paternal relatives by analyzing large numbers of male relative pairs (536) separated by one to seven meioses. A total of 96 mutations were observed in 162 meioses of father–son pairs, and other closely related male pairs were able to be differentiated after 1, 2, 3, 4, 5, 6 and 7 meiosis in 44%, 69%, 68%, 85%, 0%, 100% and 100% of cases, respectively. The multiplex offers a noticeable enhancement in the ability to differentiate paternally related males compared with the 13 RM Y STR set. We envision the future application of our 19 RM Yplex in criminal cases for the exclusion of male relatives possessing matching standard Y STR profiles and in familial searching with unknown suspects. It represents a step towards the complete individualization of closely related males.

Forensic features and phylogenetic analyses of the population of Nayagarh (Odisha), India using 23 Y-STRs

AIM

The present study was designed to explore the STR diversity and genomic history of the inhabitants of Nayagarh district of Odisha, India. We also tested the proficiency of the most recent, new generation PowerPlex^R Y23 multiplex system for forensic characterisation and to decipher the phylogenetic affinities.

SUBJECTS AND METHODS

The genetic diversity and polymorphism among 236 healthy unrelated male volunteers from Nayagarh district of Odisha, India was investigated. This investigation was carried out via 23 Y-chromosomal STRs using capillary electrophoresis.

RESULT

A total 223 unique haplotypes were reported. Discrimination capacity (DC), gene diversity (GD) and power of discrimination (PD) were observed as 0.945, 0.999999999998333, and 0.99999999999794, respectively. Polymorphic information content (PIC) and matching probability (PM) were reported as 0.999999999925535 and 2.06 × 10^-12, respectively. Simultaneously, the haplogroup analysis characterised with C2, E1b1a, E1b1b, G2a, H1, I2a, J2a, J2b, L, O, O1, O2, Q, R1a, R2, and T haplogroups, disclosing the possible geographical relatedness of the studied population to different areas of the world.

CONCLUSION

Phylogenetic analysis with previously reported Indian and Asian populations showed the genetic closeness of the studied population to different Indian populations and the Bangladeshi population of Dhaka, whereas the Bhotra population of Odisha and Han population of China showed much less genetic affinity.

Developmental Validation of a Rapidly Mutating Y-STR Panel Labeled by Six Fluoresceins for Forensic Research

The male-specific region of the human Y chromosome is a useful genetic marker for genealogical searching, male inheritance testing, and male DNA mixture deconvolution in forensic studies. However, the Y chromosomal short tandem repeats (Y-STRs) are difficult to distinguish among related males due to their low/medium mutation rate. In contrast, rapidly mutating (RM) Y-STRs exhibit unusually high mutation rates and possess great potential for differentiating male lineages. In this study, we developed a novel Y-STRs multiplex amplification assay of 32 RM Y-STRs by fragment analysis using six dye-labeled technologies (FAM, HEX, TAMRA, ROX, VIG, and SIZ). The development and the validation of the kit were carried out in accordance with the Scientific Working Group guidelines on DNA Analysis Methods. Identical allelic profiles of the 32 RM Y-STRs using a DNA 9948 sample as the positive control could be observed at different concentrations of PCR reagents. Further, the RM Y-STRs did not show cross-reactions with other common animal species, and the developed assay could tolerate interferences from common PCR inhibitors and mixed DNA samples. More importantly, the kit showed relatively high sensitivity and could detect trace DNA samples. Genetic distributions of 32 RM Y-STRs in the Guizhou Han population revealed that these RM Y-STRs showed relatively high genetic diversities. In conclusion, the RM Y-STR assay developed here showed good species specificity, high sensitivity, tolerance to inhibitors, and sample compatibility, which can be viewed as a highly efficient tool with high discrimination capacity for forensic male differentiation.

Sequence Variations of 31 Υ-Chromosomal Short Tandem Repeats Analyzed by Massively Parallel Sequencing in Three U.S. Population Groups and Korean Population

BACKGROUND

Rapidly mutating (RM) Y-chromosomal short tandem repeats (Y-STRs) have been demonstrated to increase the possibility of distinguishing between male relatives due to a higher mutation rate than conventional Y-STRs. Massively parallel sequencing (MPS) can be useful for forensic DNA typing as it allows the detection of sequence variants of many forensic markers. Here, we present sequence variations of 31 Y-STRs including nine RM Y-STRs (DYF387S1, DYF399S1, DYF404S1, DYS449, DYS518, DYS570, DYS576, DYS612, and DYS627), their frequencies, distribution, and the gain in the number of alleles using MPS.

METHODS

We constructed a multiplex MPS assay capable of simultaneously amplifying 32 Y-chromosomal markers, producing amplicons ranging from 85-274 bp. Barcoded libraries from 220 unrelated males from four populations-African Americans, Caucasians, Hispanics, and Koreans-were generated via two-step polymerase chain reaction and sequenced on a MiSeq system. Genotype concordance between the capillary electrophoresis (CE) and MPS method and sequence variation of Y-STRs were investigated.

RESULTS

In total, 195 alleles were increased by MPS compared to CE-based alleles (261 to 456). The DYS518 marker showed the largest increase due to repeat region variation (a 3.69-fold increase). The highest increase in the number of alleles due to single nucleotide polymorphisms in the flanking region was found in DYF399S1. RM Y-STRs had more diverse sequences than conventional Y-STRs. Furthermore, null alleles were observed in DYS576 due to primer-binding site mutation, and allele drop-outs in DYS449 resulted from low marker coverage of less than the threshold.

CONCLUSION

The results suggest that the expanded and discriminative MPS assay could provide more genetic information for Y-STRs, especially for RM Y-STRs, and could advance male individualization. Compiling sequence-based Y-STR data for worldwide populations would facilitate the application of MPS in the field of forensic genetics and could be applicable in solving male-related forensic cases.

Improving the regional Y-STR haplotype resolution utilizing haplogroup-determining Y-SNPs and the application of machine learning in Y-SNP haplogroup prediction in a forensic Y-STR database: A pilot study on male Chinese Yunnan Zhaoyang Han population

Improving the resolution of the current widely used Y-chromosomal short tandem repeat (Y-STR) dataset is of great importance for forensic investigators, and the current approach is limited, except for the addition of more Y-STR loci. In this research, a regional Y-DNA database was investigated to improve the Y-STR haplotype resolution utilizing a Y-SNP Pedigree Tagging System that includes 24 Y-chromosomal single nucleotide polymorphism (Y-SNP) loci. This pilot study was conducted in the Chinese Yunnan Zhaoyang Han population, and 3473 unrelated male individuals were enrolled. Based on data on the male haplogroups under different panels, the matched or near-matching (NM) Y-STR haplotype pairs from different haplogroups indicated the critical roles of haplogroups in improving the regional Y-STR haplotype resolution. A classic median-joining network analysis was performed using Y-STR or Y-STR/Y-SNP data to reconstruct population substructures, which revealed the ability of Y-SNPs to correct misclassifications from Y-STRs. Additionally, population substructures were reconstructed using multiple unsupervised or supervised dimensionality reduction methods, which indicated the potential of Y-STR haplotypes in predicting Y-SNP haplogroups. Haplogroup prediction models were built based on nine publicly accessible machine-learning (ML) approaches. The results showed that the best prediction accuracy score could reach 99.71% for major haplogroups and 98.54% for detailed haplogroups. Potential influences on prediction accuracy were assessed by adjusting the Y-STR locus numbers, selecting Y-STR loci with various mutabilities, and performing data processing. ML-based predictors generally presented a better prediction accuracy than two available predictors (Nevgen and EA-YPredictor). Three tree models were developed based on the Yfiler Plus panel with unprocessed input data, which showed their strong generalization ability in classifying various Chinese Han subgroups (validation dataset). In conclusion, this study revealed the significance and application prospects of Y-SNP haplogroups in improving regional Y-STR databases. Y-SNP haplogroups can be used to discriminate NM Y-STR haplotype pairs, and it is important for forensic Y-STR databases to develop haplogroup prediction tools to improve the accuracy of biogeographic ancestry inferences.

RMplex: An efficient method for analyzing 30 Y-STRs with high mutation rates

Y-chromosomal short tandem repeats (Y-STRs) with high mutation rates are recognized as valuable genetic markers for differentiating paternally related men, who typically cannot be separated with standard Y-STRs, and were shown to provide paternal lineage differentiation on a higher resolution level than standard Y-STRs. Both features make Y-STRs with high mutation rates relevant in criminal casework, particularly in sexual assault cases involving highly unbalanced male-female DNA mixtures that often fail autosomal forensic STR profiling for the male donor. Previously, the number of known Y-STRs with mutation rates higher than 10^-2 per locus per generation termed rapidly mutating Y-STRs (RM Y-STRs) was limited to 13, which has recently been overcome by the discovery and characterization of 12 additional RM Y-STRs. Here, we present the development and validation of RMplex, an efficient genotyping system for analyzing 30 Y-STRs with high mutation rates, including all currently known RM Y-STRs, using multiplex PCR with capillary electrophoresis (CE) or massively parallel sequencing (MPS), overall targeting a total of 44 male-specific loci. If previously unavailable, repeat number assignations were provided based on newly generated MPS data. Validation tests based on the CE method demonstrated that the results were both repeatable and reproducible, full profiles were achieved with minimal input DNA of 250 pg for RMplex 1 and 100 pg for RMplex 2, and in the presence of inhibitors, or with a surplus of female DNA, the assays performed reasonably well. Application of RMplex to differentiate between paternally related men was exemplified in 32 males belonging to five different paternal pedigrees. Given further successful forensic validation testing, we envision the future application of RMplex in criminal cases where it is suspected, or cannot be excluded, that the crime scene trace originated from a male relatives of the suspect who is highlighted with standard Y-STR matching. Other applications of RMplex are in criminal cases without known suspects to differentiate between male relatives highlighted in familial searching based on standard Y-STR matching.

The Y-STR landscape of coastal southeastern Han: Forensic characteristics, haplotype analyses, mutation rates, and population genetics

The Y-STR landscape of Coastal Southeastern Han (CSEH) living in Chinese southeast areas (including Guangdong, Fujian, and Zhejiang provinces) is still unclear. We investigated 62 Y-STR markers in a reasonably large number of 1021 unrelated males and 1027 DNA-confirmed father-son pairs to broaden the genetic backgrounds of CSEH. In total, 85 null alleles, 121 off-ladder alleles, and 95 copy number variants were observed, and 1012 distinct haplotypes were determined with the overall HD and DC values of 0.999974 and 0.9912. We observed 369 mutations in 76 099 meiotic transfers, and the average estimated Y-STR mutation rate was 4.85 × 10^-3 (95% CI, 4.4 × 10^-3 -5.4 × 10^-3 ). The Spearman correlation analyses indicated that GD values (R² = 0.6548) and average allele sizes (R² = 0.5989) have positive correlations with Y-STR mutation rates. Our RM Y-STR set including 8 candidate RM Y-STRs, of which DYS534, DYS630, and DYS713 are new candidates in CSEH, distinguished 18.52% of father-son pairs. This study also clarified the population structures of CSEH which isolated in population-mixed South China relatively. The strategy, SM Y-STRs for familial searching and RM Y-STRs for individual identification regionally, could be applicable based on enough knowledge of the Y-STR mutability of different populations.

Insights From Y-STRs: Forensic Characteristics, Genetic Affinities, and Linguistic Classifications of Guangdong Hakka and She Groups

Guangdong province is situated in the south of China with a population size of 113.46 million. Hakka is officially recognized as a branch of Han Chinese, and She is the official minority group in mainland China. There are approximately 25 million Hakka people who mainly live in the East and North regions of China, while there are only 0.7 million She people. The genetic characterization and forensic parameters of these two groups are poorly defined (She) or still need to be explored (Hakka). In this study, we have genotyped 475 unrelated Guangdong males (260 Hakka and 215 She) with Promega PowerPlex^® Y23 System. A total of 176 and 155 different alleles were observed across all 23 Y-STRs for Guangdong Hakka (with a range of allele frequencies from 0.0038 to 0.7423) and Guangdong She (0.0047–0.8605), respectively. The gene diversity ranged from 0.4877 to 0.9671 (Guangdong Hakka) and 0.3277–0.9526 (Guangdong She), while the haplotype diversities were 0.9994 and 0.9939 for Guangdong Hakka and Guangdong She, with discrimination capacity values of 0.8885 and 0.5674, respectively. With reference to geographical and linguistic scales, the phylogenetic analyses showed us that Guangdong Hakka has a close relationship with Southern Han, and the genetic pool of Guangdong Hakka was influenced by surrounding Han populations. The predominant haplogroups of the Guangdong She group were O2-M122 and O2a2a1a2-M7, while Guangdong She clustered with other Tibeto-Burman language-speaking populations (Guizhou Tujia and Hunan Tujia), which shows us that the Guangdong She group is one of the branches of Tibeto-Burman populations and the Huonie dialect of She languages may be a branch of Tibeto-Burman language families.

Forensic features and genetic legacy of the Baloch population of Pakistan and the Hazara population across Durand line revealed by Y-chromosomal STRs

The Hazara population across Durand line has experienced extensive interaction with Central Asian and East Asian populations. Hazara individuals have typical Mongolian facial appearances and they called themselves descendants of Genghis Khan's army. The people who speak the Balochi language are called Baloch. Previously, a worldwide analysis of Y-chromosomal haplotype diversity for rapidly mutating (RM) Y-STRs and with PowerPlex Y23 System (Promega Corporation Madison, USA) kit was created with collaborative efforts, but Baloch and Hazara population from Pakistan and Hazara population from Afghanistan were missing. In the current study, Yfiler Plus PCR Amplification Kit loci were examined in 260 unrelated Hazara individuals from Afghanistan, 153 Hazara individuals, and 111 Balochi individuals from Baluchistan Pakistan. For the Hazara population from Afghanistan and Pakistan overall, 380 different haplotypes were observed on these 27 Y-STR loci, gene diversities ranged from 0.51288 (DYS389I) to 0.9257 (DYF387S1), and haplotype diversity was 0.9992. For the Baloch population, every individual was unique at 27 Y-STR loci; gene diversity ranged from 0.5718 (DYS460) to 0.9371(DYF387S1). Twelve haplotypes were shared between 178 individuals, while only two haplotypes among these twelve were shared between 87 individuals in Hazara populations. Rst and Fst pairwise genetic distance analyses, multidimensional scaling plot, neighbor-joining tree, linear discriminatory analysis, and median-joining network were performed, which shed light on the history of Hazara and Baloch populations. The results of our study showed that the Yfiler Plus PCR Amplification Kit marker set provided substantially stronger discriminatory power in the Baloch population of Pakistan and the Hazara population across the Durand line.

Forensic features and genetic structure of 20 autosomal STR loci in the Han population of Ningde City, Southeastern China

BACKGROUND

Short tandem repeat (STR) loci are widely used in forensic medicine and population genetics.

AIM

To profile 20 autosomal STR loci using the SureID^® 21 G Human STR Identification Kit.

SUBJECTS AND METHODS

Samples were obtained from 1412 unrelated Chinese Han individuals from Ningde City, Southeastern China and 20 autosomal STR loci were profiled using the SureID^® 21 G Human STR Identification Kit.

RESULTS

A total of 261 alleles were observed among 1412 unrelated individuals and the corresponding allelic frequencies ranged from 0.5464 to 0.0004. The combined power of discrimination and exclusion of the 20 autosomal STR loci were 0.99999999999999999922 and 0.999999340285752, respectively. There was no significant deviation from Hardy-Weinberg equilibrium (HWE) and minimal departure from linkage equilibrium (LE) for two pairwise combinations of loci after sequential Bonferroni correction. In the population comparison, phylogenetic analysis was performed between the Han population and other relevant populations on the basis of the shared autosomal STR genotyping. Moreover, the neighbor-joining tree and principal component analysis were analysed based on the Nei's standard genetic distance.

CONCLUSION

The population comparison revealed that the structure of the Ningde Han population was similar to the structure of southern Han populations in China and was significantly different to the other Chinese ethnic groups, such as Kyrgyz, Uzbek, Kazakh, Uyghur, Manchu from Xinjiang and Mongols.

Ethnic fragmentation and degree of urbanization strongly affect the discrimination power of Y-STR haplotypes in central Sahel

Y chromosome short tandem repeats (Y-STRs) are commonly used to identify male lineages for investigative and judicial purposes and could represent the only source of male-specific genetic information from unbalanced female-male mixtures. The Yfiler Plus multiplex, which includes twenty conventional and seven rapidly-mutating Y-STRs, represents the most discriminating patrilineal system commercially available to date. Over the past five years, this multiplex has been used to analyze several Eurasian populations, with a reported discrimination capacity (DC) approaching or corresponding to the highest possible value. However, despite the inclusion of rapidly mutating Y-STRs, extensive haplotype sharing was still reported for some African populations due to a number of different factors affecting the effective population size. In the present study, we analyzed 27 Y-STRs included in the Yfiler Plus multiplex and 82 Y-SNPs in central Sahel (northern Cameroon and western Chad), an African region characterized by a strong ethnic fragmentation and linguistic diversity. We evaluated the effects of population sub-structuring on genetic diversity by stratifying a sample composed of 431 males according to their ethnicity (44 different ethnic groups) and urbanization degree (four villages and four towns). Overall, we observed a low discrimination capacity (DC = 0.90), with 71 subjects (16.5 %) sharing 27 Y-STR haplotypes. Haplotype sharing was essentially limited to subjects with the same binary haplogroup, coming from the same location and belonging to the same ethnic group. Haplotype sharing was much higher in rural areas (average DC = 0.83) than urban settlements (average DC = 0.96) with a significant correlation between DC and census size (r = 0.89; p = 0.003). Notably, we found that genetic differentiation between villages from the same country (Φ_ST = 0.14) largely exceeded that found among countries (Φ_ST = 0.02). These findings have important implications for the choice of the appropriate reference population database to evaluate the statistical relevance of forensic Y-haplotype matches.

Genetic characterisation and forensic importance of 20 Y-STRs in Han population from Anshan, Northeast of China

BACKGROUND

With a population of over 1.4 billion and 56 ethnic groups, China is the largest country in the world in terms of population. Han is the main ethnic group of China (93%).

AIM

To provide genetic data of Y chromosomal STRs from Anshan City, Northeast of China, for the first time, which will serve as a reference database for forensic and population studies.

SUBJECTS AND METHODS

We report data of 20 Y-chromosomal short tandem repeats (YSTRs) genotyped with the Goldeneye^® 20Y kit in 270 Han individuals residing in Anshan City of China.

RESULTS

A total of 170 alleles were observed on 20 Y-STRs. The gene diversities varied from 0.3460 (DYS391) to 0.9692 (DYS385). Overall haplotype diversity was almost 1 with 261 unique haplotypes, while the discrimination capacity (DC) was 0.9814. Pairwise Rst and Fst genetic analyses, MDS plot, N-J tree and PCA showed the genetic structure of Anshan Han population was significantly different from other minority groups like Tibetans and Kazakhs.

CONCLUSIONS

Results of this study showed that Goldeneye^® 20Y system loci have strong discriminatory power in the Anshan Han population of China which makes this kit suitable for forensic applications in this ethnic group.

Geographical structuring and low diversity of paternal lineages in Bahrain shown by analysis of 27 Y-STRs

We have determined the distribution of Y-chromosomal haplotypes and predicted haplogroups in the ethnically diverse Kingdom of Bahrain, a small archipelago in the Arabian Gulf. Paternal population structure within Bahrain was investigated using the 27 Y-STRs (short tandem repeats) in the Yfiler Plus kit to generate haplotypes from 562 unrelated Bahraini males, sub-divided into four geographical regions—Northern, Capital, Southern and Muharraq. Yfiler Plus provided a significant improvement over the 17-locus Yfiler kit in discrimination capacity (from 77% to 87.5% overall), but discrimination capacity differed widely between regions from 98.4% in Muharraq to 75.2% in the Northern region, an unusually low value possibly resulting from recent rapid population expansion. Clusters of closely related male lineages were seen, with only 79.4% of donors displaying unique haplotypes and 59% of instances of shared haplotypes occurring within, rather than between, regions. Haplogroup prediction indicated diverse origins of the population with a predominance of haplogroups J2 and J1, both typical of the Arabian Peninsula, but also haplogroups such as B2 and E1b1a likely originating in Africa, and H, L and R2 likely indicative of migration from South Asia. Haplogroup frequencies differed significantly between regions, with J2 significantly more common in the Northern region compared with the Southern, possibly due to differential settlement by Baharna and Arabs. Our study shows that paternal lineage population structure can exist even over small geographical scales, and that highly discriminating genetic tools are required where rapid expansions have occurred within tightly bounded populations.

Comprehensive genetic structure analysis of Han population from Dalian City revealed by 20 Y-STRs

BACKGROUND

Dalian is a city formed in the 1880s in Liaoning province, Northeastern China with a population of 6.69 million now. Han is the largest ethnic group not only across Mainland China (92%) and Taiwan (97%) but also considered to be the largest ethnic group of the world contributing to above 18% of world's population.

METHODS

In the current study, we genotyped Goldeneye® 20Y System loci in 879 unrelated male individuals from the Han ethnic group in Dalian city and calculated the forensic parameters of the 20 Y-STR loci.

RESULTS

In total, we observed 855 haplotypes, among which 835 (94.99%) were unique. The discrimination capacity (DC) of overall Goldeneye® 20Y System is 97.27% and it slightly reduces to 96.93% when only Y-filer® set of 17 Y-STRs were used, which mitigates using the extended set of markers in this population. We found DYS388 showed the lowest gene diversity (0.5151), whereas DYS389II showed the highest gene diversity (0.7621) in single copy Y-STR, and DYS385 showed the highest gene diversity (0.9683) among all.

CONCLUSION

Multidimensional scaling (MDS) analysis based upon pairwise Rst genetic distance showed difference among Han population from the east to the west and from the north to the south. We also predicted haplogroups using Y-STR haplotypes, which showed the dominance of Haplogroup O (65.2%) followed by Haplogroup C (14.5%) in Dalian Han population. Moreover, we found 10 individuals showed a null allele at the DYS448 in our samples. We also performed linear discriminatory analysis (LDA) between Han and other prominent Chinese minority ethnic groups. We presented Y-STRs data in the Y-Chromosome Haplotype Reference Database (YHRD) for the future forensic and other usage.

Genetic characterization of 15 autosomal STRs in the interior Sindhi population of Pakistan and their phylogenetic relationship with other populations

Genetic structure of a population can be influenced by evolutionary processes and cultural histories which can alter the frequencies of different variants at particular genetic markers. These characteristics make DNA evidence suitable for forensic applications. Little relevant data are available from the interior Sindhi population; thus, in the current study, we have investigated 15 autosomal STRs in 181 unrelated individuals belonging to the interior parts of Sindh Pakistan, to establish its lineage and parameters of forensic interest. These STRs revealed a high power of discrimination (CPD), power of exclusion (CPE) and matching probability (CMP) are 0.9999999999999999968997, 0.99998612 and 3.1003 × 10^-18 respectively. The genetic distances, neighbour-joining (NJ) tree, interactivity test and principal component analysis (PCA) based on 15 autosomal STR loci showed that the interior Sindhi population had a closer genetic relationship with Pakistani populations and distant relationships with regional (India and Afghanistan) populations. The present findings exhibited that STRs included in AmpFLSTR Identifiler kit (Applied Biosystems) are genetically polymorphic in the interior Sindhi population of Pakistan. This study provides valuable population genetic data for the genetic information study, forensic human individual identification and paternity testing.

Phylogenetic relationship and genetic history of Central Asian Kazakhs inferred from Y-chromosome and autosomal variations

The Xinjiang Uyghur Autonomous Region of China (XUARC) with 47 ethnic groups is a very colorful ethnic region of China, harboring abundant genetic and cultural diversity. The Kazakhs are the third largest ethnic group (7.02%) after Uyghur (46.42%) and Han (38.99%) in Xinjiang, but their genetic diversity and forensic characterization are poorly understood. In the current study, we genotyped 15 autosomal short tandem repeat (STR) loci and ten Y-STRs in 889 individuals (659 male and 230 female) collected from Kazak population of the Ili Kazak Autonomous Prefecture using AGCU Expressmarker 16 and 10Y-STR Kit (EX16 + 10Y). For autosomal STRs, we observed a total of 174 different alleles ranging from 6 to 34.2 repeat units and FGA showed the greatest power of discrimination (20 alleles) in Ili Kazakh population. We have not observed departures from Hardy-Weinberg equilibrium (HWE) after sequential Bonferroni correction and only found a minimal departure from linkage equilibrium (LE) for a very small number of pairwise combinations of loci. The combined power of exclusion (CPE) was 0.99999998395 and combined power of discrimination (CPD) was 99.999999999999999798%. For Y-STRs, we observed a total of 496 different haplotypes in these ten Y-STR loci. The gene diversities ranged from 0.5023 (DYS391) to 0.8357 (DYS385a/b). The overall haplotype diversity (GD) was 0.9985 with random matching probability (RMP) of 0.0015. The results of population genetic analysis based on both autosomal and Y-chromosome STRs demonstrated that the genetic affinity among populations is generally consistent with ethnic, linguistic, and continental geographical classifications.

Forensic genealogy, bioethics and the Golden State Killer case

A case study will be used to examine specific issues of bioethics and forensic science that occur in forensic investigative genealogical searching, which include genetic privacy, discrimination and public safety concerns. The forensic investigative process and various investigative DNA tools will also be described. The Golden State Killer Case (1) will be examined to highlight and discuss forensic ethical issues to develop an ethical framework, as well as provide recommended solutions to pressing public safety and privacy issues facing crime laboratories and criminal investigators. Use of the ethical concept of proportionality (2) will be utilized to contrast and balance competing ethical concerns.

Population genetics of 15 autosomal STR loci in the Han population of Ili Kazakh Autonomous Prefecture, Northwestern China

PURPOSE

China harbors 56 ethnic groups and Han accounts for >92% of the total Chinese population. We investigated the frequencies of 15 autosomal short tandem repeat (STR) loci in the Han population of the Ili Kazakh Autonomous Prefecture with the aim of expanding the available population information in human genetics databases and for forensic DNA analysis.

SUBJECTS AND METHODS

We explored the genetic characteristics of 15 autosomal STR loci in 552 unrelated Chinese Han individuals from Ili Kazakh Autonomous Prefecture, Northwestern China using the AmpFISTR Identifiler PCR Amplification Kit. Moreover, phylogenetic analysis was performed between the Han population and other relevant populations based on the autosomal STR genotyping. The neighbor-joining tree and principle component analysis were generated based on the Nei's standard genetic distance and allelic frequencies, respectively.

RESULTS

A total of 171 alleles were observed among 552 unrelated individuals and allelic frequencies ranged from 0.5145 to 0.0009. The combined power of discrimination and combined power of exclusion of the 15 autosomal STR loci were 0.9999999999999999964 and 0.999998243616671, respectively.

CONCLUSIONS

Population comparison revealed that the Ili Han population were lining up together with other Han populations in China while showing significant differences from other Chinese and worldwide populations.

Population data of 23 Y STRs from Manchu population of Liaoning Province, Northeast China

Mongol-like-horsemen-turned-merchants from Manchuria are known as Manchus, originally their homeland was centered around what is nowadays the city of Shenyang in Northeast China. Previously, worldwide analysis of Y-chromosomal haplotype diversity for 23 STR loci and Y-STR databases with PowerPlex® Y23 System (Promega Corporation Madison, USA) kit were created with collaborative efforts, but Manchu population data was missing. In current study, PowerPlex® Y23 System loci were examined in 328 unrelated Manchu male individuals from Xiuyan and Huanren Manchu autonomous counties in Liaoning province, to calculate the forensic parameters of the 23 STR loci. A total of 323 different haplotypes were observed on these 23 Y-STR loci. The gene diversities ranged from 0.3820 (DYS391) to 0.9696 (DYS385a, b). The overall haplotype diversity was 0.9999 ± 0.0002 at PowerPlex® Y23 System. Rst pairwise analyses, multidimensional scaling plot, and linear discriminatory analysis showed the genetic structure of Manchu population was significantly different from some of Chinese populations like Tibetan and Uyghur. Results of our study showed that PowerPlex® Y23 System marker set provided substantially stronger discriminatory power in Manchu population of China.

Genetic analysis of 12 X-STRs for forensic purposes in Liaoning Manchu population from China

X-chromosomal short tandem repeats (X-STRs) have been widely used in forensic practice involving complicated cases of kinship and also play an increasingly important role in population genetics. X-STRs have been studied in regional populations of China but there is a lack of data for the Manchu population. In this study, we have investigated the forensic genetic properties of 12 X-STRs in the Investigator Argus X-12 Kit (QIAGEN, Hilden, Germany) in 772 Manchu (male = 514, female = 258) individuals from the Xiuyan and Huanren Manchu autonomous counties of Liaoning province. We observed a total of 166 alleles at 12 X-STR loci with allele frequencies ranging from 0.001295to 0.615285. The most polymorphic locus was DXS10135 with 24 alleles while DXS7423 was the least polymorphic locus with 5 alleles. We found significant linkage disequilibrium (LD) between the following pairs of markers for males: DXS10103/DXS10101, DXS10135/DXS10146, DXS10101/DXS10148, DXS10135/DXS10148, DXS7423/DXS10148 and DXS10079/DXS10148. For females, LD was only observed for DXS10103/DXS10101. The combined power of discrimination was 0.9999999979699 for males and 0.999999999999998 for females. The numbers of observed haplotypes in Manchu males were 310, 172, 182 and 172 in four linkage groups; LG1, LG2, LG3 and LG4, respectively, however, these linkage groups did not form stable haplotypes as indicated by linkage equilibrium (LE) of STRs within the groups and significant LD between the groups. This study represents an extensive report on X-STR marker variation in the Manchu population for forensic applications and population genetic studies.

Discriminating power of rapidly mutating Y-STRs in deep rooted endogamous pedigrees from Sindhi population of Pakistan

Rapidly mutating Y-STRs (RM Y-STRs) have been paid much attention in recent years. The 13 RM Y-STRs (DYF387S1, DYF399S1, DYF403S1a/b, DYF404S1, DYS449, DYS518, DYS526I/II, DYS547, DYS570, DYS576, DYS612, DYS626, and DYS627) have been proved to have substantially higher haplotype diversity and discrimination capacity than conventionally used Y-STRs indicating the considerable power in paternal lineage differentiation in endogamous populations, separation of which is usually impossible with standard Y-STRs. In current study, we analyzed the RM Y-STRs and PowerPlex® Y23 System in 216 male relatives from 18 deep rooted endogamous Sindhi families from Pakistan. Mutations were frequently observed at DYF399S1, DYS449, DYS518DYS547 and DYF403S1b2 loci, which are known to mutate more rapidly than other RM Y-STRs. Overall differentiation rate with RM Y-STRs was as high as 32.88%, while those with PowerPlex® Y23 System and AmpFℓSTR® Yfiler™ kit were 6.85% and 3.65% respectively. The differentiation rate of RM Y-STRs was 29.22% and 26.03% higher than those of AmpFlSTR® Yfiler™ kit and PowerPlex® Y23 System, respectively.

Rapidly mutating Y-STRs study in Chinese Yi population

Y-chromosomal short tandem repeats (Y-STRs) have been widely used in forensic analysis and population genetics. With low to moderate mutation rates, conventional Y-STR panels, including commercially available Y-STR kits, enable the identification of male pedigrees but typically fail to differentiate related male individuals. The introduction of rapidly mutating Y-chromosomal short tandem repeats (RM Y-STRs) with higher mutation rates (μ > 10^-2) has been demonstrated to increase the discrimination capacity of unrelated men and the differentiation rate of related men compared with standard Y-STRs. To date, several studies have been performed worldwide. Here, 260 father-son pairs from Chinese Yi population were investigated, and 18.8% of them were differentiated with the 13 RM Y-STR markers, which was close to the theoretical estimate of 19.5% based on the mutation rates of these markers. Among the 57 mutations observed, repeat gains were more common than repeat losses (1.48:1), and one-step mutations were more common than two-step mutations (27.5:1). Locus-specific mutation rates ranged from < 3.85 × 10^-3 (95% CI 0.00-1.41 × 10^-2) to 3.85 × 10^-2 (95% CI 1.86 × 10^-2-6.96 × 10^-2), with an average mutation rate of 1.46 × 10^-2 (95% CI 1.11 × 10^-2-1.89 × 10^-2). Furthermore, we combined the father-son pair data from the present study with the data from the previous studies, generating an overall mutation rate of 1.70 × 10^-2. The high differentiation rate obtained in the present study indicates the suitability of RM Y-STRs to distinguish paternal lineages in Chinese Yi population.

Population data and phylogenetic structure of Han population from Jiangsu province of China on GlobalFiler STR loci

Forensic statistical parameters based on allelic frequencies of commonly used short tandem repeats were estimated for the Han population of Jiangsu province from P.R. China. The 6-dye GlobalFiler™ PCR amplification kit incorporates 21 autosomal STRs, providing reliable DNA typing results with enhanced the power of discrimination. Here, we analyzed the GlobalFiler™ STR loci in 516 unrelated individuals from Jiangsu Han population. A total of 256 alleles were observed ranging between 5 and 35.2 repeat units, and SE33 showed the greatest power of discrimination (34 alleles) in Jiangsu Han population. Most of the loci were found to be in the Hardy-Weinberg equilibrium after the Bonferroni correction with the exception of D3S1358. The combined power of exclusion (CPE) was 0.999999996353609, and the combined match probability (CMP) was 3.64 × 10^-25. Phylogenetic parameters including pairwise genetic distances showed that Han population living in Jiangsu had closest genetic relationship with other East Asian populations. The present study provides precise reference database for forensic applications and population genetic studies.