Population genetic study of six closely linked groups of X-STRs in a Japanese population

Construction of 13-locus X-STR multiplex PCR system that reinforces Argus X-12 kit discrimination capacity: Application to the Malay population

Closely linked groups of markers on the X chromosome are very useful for testing complex kinship relationships involving X-STR transmission. The Argus X-12 kit, a unique commercially available kit, can obtain haplotypes of 4 linkage groups (LGs) consisting of 3 markers. Although many population data have been reported for forensic purposes, differences in discrimination ability exist between LG1 and LG2, 3, and 4 in East Asian populations, and the data of this kit would become more useful if the discrimination ability of the latter groups were increased. Therefore, for matches found using this kit for some linkage group data, then to increase the identification ability, we additionally introduced 13 X-STR loci and established a method allowing comparison using data from 25 loci. The 13X-STRs add two locus data to each of LG2, 3, and 4, and also add two closely linked group (CLG) data between LG2 and 3 and LG3 and 4 in one multiplex PCR. Assessment of this method for a Malay population for which data by Argus X-12 had already been reported showed that the frequencies of distinct haplotypes in LG2, 3, and 4 were increased by 33.0-42.6 %, and frequencies of unique haplotypes increased by 45.4-59.2 %. The respective haplotype diversity values of the additional 3-locus and 4-locus CLGs were 0.9838 and 0.9939, which helps to improve discriminatory power and to predict recombination locations on the X chromosome. Although we have been testing these loci with Japanese subjects, this system would also be useful for the Malay population.

X-chromosomal STRs for genetic composition analysis of Guizhou Dong group and its phylogenetic relationships with other reference populations

BACKGROUND

X-chromosomes show a specific genetic mode, which makes genetic markers on the X chromosome play crucial roles in forensic research and human evolution. Dong group, one of 55 minority groups in China, live in Guizhou, Guangxi and Hunan provinces. Even though some genetic data of Y chromosomal short tandem repeats (STRs) and autosomal insertion/deletion polymorphism (InDels) in Dong groups have been reported, there is little research about X-STRs in the Dong group.

AIM

Purposes of this study are to investigate allelic distributions and forensic statistical parameters of 19 X-STRs in the Guizhou Dong group, and explore the genetic composition of the Guizhou Dong group and its phylogenetic relationships with other reference populations.

SUBJECTS AND METHODS

507 Dongs (272 males and 235 females) living in Guizhou province were typed using the AGCU X19 STR kit. Allelic frequencies and forensic parameters of 19 X-STRs in the Guizhou Dong group were calculated. Population genetic analyses of Guizhou Dong and other 17 reference populations were conducted using D_A genetic distances, phylogenetic tree, principal component analysis and multidimensional scaling.

RESULTS

A total of 230 alleles of 19 X-STRs were identified in all Dongs. The frequencies of 19 loci ranged from 0.0013 to 0.6838. Cumulative power of discrimination in males (PDM), Cumulative power of discrimination in females (PDF), four different kinds of mean exclusion chance (MEC_Kruger, MEC_Kishida, MEC_Desmarais and MEC_Desmarais_du) values of 19 X-STRs in all individuals were 0.999999999999761, 0.9999999999999999999993951, 0.999999964841617, 0.999999999997261, 0.999999999997297 and 0.999999993623172, respectively. Besides, genetic polymorphisms of seven linkage clusters ranged from 0.9381 to 0.9963. In addition, these seven groups showed high polymorphism information content (PIC), PDM, PDF, MEC_Kruger, MEC_Kishida, MEC_Desmarais and MEC_Desmarais_duo values. Population genetic analyses of Guizhou Dong and other 17 reference populations showed that the Guizhou Dong group had close genetic relationships with surrounding Tai-Kadai-speaking, Hmong-Mien-speaking and Han groups.

CONCLUSION

Nineteen X-STRs displayed high genetic diversities and could be employed for forensic personal identification and paternity analysis in the Guizhou Dong group. Close genetic affinities between Guizhou Dong and surrounding populations were observed based on the 19 X-STRs in 17 reference populations.

Phylogenetic analyses of the 19 STR loci in X chromosome revealed discriminant forensic characteristics for Chinese Daur and Oroqen minorities

In respect of forensic genetics, X-STRs are widely applied for deficiency paternity cases. Given the popularization of AGCU-X19 STR Kit in China, there has been investigation conducted into the genetic data and forensic parameters of 19 X-STR loci in many of the Chinese ethnic groups, which makes it possible to perform nationwide phylogenetic comparation. To evaluate the allele and haplotype diversity of 19 X-STR loci and to explore their forensic efficiency in the Daur and Oroqen minorities, unrelated healthy Daur (n = 86) and Oroqen (n = 165) individuals were recruited from Heilongjiang province, so as to reveal the phylogenetic relationship between the two minorities and other Chinese ethnic groups. Of the Daur and Oroqen minorities, 172 and 183 alleles at the 19 X-STR loci were observed, respectively. Haplotype diversity exceeded 0.9 among all the linkage clusters. High cumulative value was observed for the power of discrimination, the probability of exclusion, and the mean exclusion chance for deficiency cases (normal trios and duo cases). As revealed by this study, the panel of 19 X-STR loci is an effective supplementary tool for the kinship test of the studied nationalities.

X-chromosomal STR based genetic polymorphisms and demographic history of Sri Lankan ethnicities and their relationship with global populations

A new 16 X-short tandem repeat (STR) multiplex PCR system has recently been developed for Sr Lankans, though its applicability in evolutionary genetics and forensic investigations has not been thoroughly assessed. In this study, 838 unrelated individuals covering all four major ethnic groups (Sinhalese, Sri Lankan Tamils, Indian Tamils and Moors) in Sri Lanka were successfully genotyped using this new multiplex system. The results indicated a high forensic efficiency for the tested loci in all four ethnicities confirming its suitability for forensic applications of Sri Lankans. Allele frequency distribution of Indian Tamils showed subtle but statistically significant differences from those of Sinhalese and Moors, in contrast to frequency distributions previously reported for autosomal STR alleles. This suggest a sex biased demographic history among Sri Lankans requiring a separate X-STR allele frequency database for Indian Tamils. Substantial differences observed in the patterns of LD among the four groups demand the use of a separate haplotype frequency databases for each individual ethnicity. When analysed together with other 14 world populations, all Sri Lankan ethnicities except Indian Tamils clustered closely with populations from Indian Bhil tribe, Bangladesh and Europe reflecting their shared Indo-Aryan ancestry.

Development of a 16 X-STR multiplex PCR system for kinship analysis and its applicability for the Sinhalese population in Sri Lanka

The study describes the development of a new multiplex PCR system that simultaneously amplifies 16 X chromosome short tandem repeats (X-STRs) loci in a single PCR reaction and its applicability on a sample of 200 from the Sinhalese population in Sri Lanka. 13 X-STR loci located in four clusters are selected for the assay (DXS10148-DXS10135-DXS8378, DXS7132-DXS10079-DXS10074-DXS10075, DXS6801-DXS6809-DXS6789 and DXS7424-DXS101-DXS7133). In addition, three single loci were also selected (DXS9902, HPRTB and DXS7423). Genomic DNA extracted using the Chelex-100 method was amplified with modified published primers and subjected to capillary gel electrophoresis. Complete DNA profiles were obtained with 0.20 ng 9947A DNA and the band sizes ranged between 100 and 320 bp with 10 loci having sizes below 237 bp. A total of 160 alleles were observed among the sample with 5-23 alleles for each locus. The forensic efficiency evaluation showed high values for the combined power of discrimination in males (1 in 1 × 10¹⁰) and females (1 in 1 × 10¹⁷). Combined mean exclusion chance (MEC) indices calculated for deficiency, normal trio and duo cases were equally high (> 0.99999). Application of the new multiplex system to two actual kinship cases of full sibling and deficient paternity suggested that these 16 short tandem repeat loci are highly appropriate for forensic and kinship testing among the Sinhalese population.

Genetic diversity, forensic feature, and phylogenetic analysis of Guizhou Tujia population via 19 X-STRs

BACKGROUND

X-chromosome short tandem repeats (X-STRs) with unique sex-linkage inheritance models play a complementary role in forensic science. Guizhou is a multiethnic province located in southwest China and some genetic evidence focusing on X-STRs for various minorities was reported. However, population data of Guizhou Tujia are scarce.

METHODS

A total of 507 Guizhou Tujia individuals were profiled using the AGCU X-19 STR kit. Allele frequencies and forensic parameters were calculated. Additionally, population genetic relationships between Guizhou Tujia and other 19 populations were explored.

RESULTS

A total of 257 alleles with the allele frequencies ranged from 0.0013 to 0.6098 were found. The combined power of discrimination in males and females and mean exclusion chances in all case scenarios were all greater than 0.99999. Population comparisons showed Guizhou Tujia had a homogeneity with all Han populations from different administrative regions, and other ethnic populations residing in Guizhou, while had obviously genetic heterogeneity with the Altaic family populations except Xibe.

CONCLUSION

Nineteen X-STRs can afford a reliable and informative database of Guizhou Tujia population for human identification and paternity testing, especially in complex biological relations. The genetic relationships of Chinese are significantly influenced by the geographic position and ethnolinguistic origin.

Population genetics, diversity, forensic characteristics of four Chinese populations inferred from X-chromosomal short tandem repeats

We genotyped 19 X-STRs included in the AGCU X19 kit in 712 unrelated Chinese individuals from four populations (Li, Hui, Tibetan, and Han) and then merged with 4156 previously genotyped subjects from 19 populations to investigate genetic relationships and population structure, as well as the association between the genetic affinity and language classification. The combined mean paternity exclusion chances and the combined probabilities of discrimination based on single allele frequencies of 19-X-STRs and haplotype frequencies of seven linkage groups were high, indicating that this set of markers was very polymorphic in the four populations studied. Therefore, this panel can complement autosomal or uniparental markers in kinship analysis and complex deficient paternity testing. Subsequently, population differentiation analyses among 23 populations based on 19 STRs and 15 populations based on over 62 million single nucleotide polymorphisms consistently demonstrated that genetic stratifications exist between the different language-speaking populations, especially Tibeto-Burman-speaking, Tungusic and Turkic-speaking populations. Our newly studied populations are genetically close to ethnolinguistically adjacent populations. Our datasets can and should be used as an allele and haplotype frequencies reference database to facilitate the use of 19-X-STRs panel in routine forensic practice.

Forensic genetic polymorphisms and population structure of the Guizhou Bouyei people based on 19 X-STR loci

Background: Guizhou province is located in southwest China with abundant genetic, linguistic and cultural diversity. The Bouyei is one of the 18 officially recognised minority groups in Guizhou, accounting for about 97% of the total Bouyei population in China. However, the genetic history and forensic characterisation of the Bouyei people is largely unknown due to a lack of genetic data.Aim: We aim to investigate genetic polymorphisms and forensic characterisation of the Guizhou Bouyei population, as well as the relationships between the Bouyei and other East Asian populations.Subjects and methods: We genotyped 19 X-STRs in 188 males and 165 females of Guizhou Bouyei using the AGCU X19 STR Kit. We estimated allele frequencies, forensic parameters and genetic distances between the Bouyei and other East Asian populations. We presented the genetic distances in a phylogenetic tree, an MDS plot and a PCA plot.Results: In Guizhou Bouyei individuals, we observed 216 alleles with corresponding frequencies ranging from 0.0019 to 0.6757. All of the six combined powers of PD_m, PD_f, MEC Krüger, MEC Kishida, MEC Desmarais and MEC Desmarais in allele diversity and haplotype diversity are larger than 0.99999995. We found genetic affinities among the Bouyei people and their geographical neighbouring populations in Guizhou, such as the Sui, Miao and Han.Conclusions: The highly polymorphic and informative forensic parameters of the 19 X-STRs in Bouyei people show the powerful potential of those markers in forensic identification and parentage tests. The genetic relationships of the Bouyei with other East Asian populations correspond well with geographic affiliations as well as linguistic classifications.

Genetic structure and forensic characterisation of 19 X-chromosomal STR loci in Guizhou Sui population

Background: Guizhou Sui people are an officially recognised ethnic group living in southwest China, but have seldom been studied genetically.Aim: To investigate the polymorphisms of 19 X-chromosome STR loci in a typical Sui population and enrich the East Asian X-STR reference database for forensic DNA analysis.Subjects and methods: A total of 400 Sui individuals (195 males and 205 females) were genotyped at 19 X-STR loci using the AGCU X19 STR Kit. The allele frequencies and forensic parameters were calculated and illustrated and the data of Guizhou Sui were merged with 18 other nationwide populations to explore genetic polymorphisms and population relationships.Results: A total of 215 alleles were observed with corresponding frequencies ranging from 0.0017-0.6512 in Sui using male and female pooled allele frequencies. Large values were observed, at least 0.9999999933, in combined powers of discrimination of Sui males and females, as well as the four mean paternity exclusion chances (MECs). The phylogenetic analysis among 19 populations showed that Sui have close genetic affinities with other Tai-Kadai populations, as well as the Sinitic populations living in southern China.Conclusions: The AGCU X-19 STRs are highly polymorphic and informative in Guizhou Sui people. The genetic relationships between Sui and other populations in China are generally consistent with the language classification and geographical distance.

Genetic structure and polymorphisms of Gelao ethnicity residing in southwest china revealed by X-chromosomal genetic markers

X-chromosome short tandem repeat markers (X-STRs), due to their special inheritance models, physical location on a single chromosome and the absence of recombination in male meiosis, play an important role in forensic and population genetics. While a series of genetic analyses focusing on the genetic diversity and forensic characteristics of X-STRs are well studied for ethnically/linguistically diverse and demographically large Chinese populations, genetic evidence from Gelao ethnicity is still sparse. Here, we genotyped the first batch of 19 X-STRs in 513 Chinese Gelao individuals (265 females and 248 males), and reported genetic polymorphisms, forensic characteristics based on the single locus and seven linkage groups. DXS10135 with the highest PIC (0.9106) and LG1 (DXS10148-DXS10135-DXS8378) with the largest HD (0.9970) are polymorphic and informative. The CPDs in Gelao males and females are respectively larger than 0.999999999997095 and 0.99999999999999999999918, and the combined MECs are larger than 0.999999975715109. Subsequently, we investigated the population relationships among 14 Chinese populations based on 19 X-STRs and among 23 populations based on 11 overlapped X-STRs. Our results revealed genetic differentiations among Tibeto-Burman, Altaic and other Chinese homogenous populations, and demonstrated that Guizhou Gelao has the genetically closer relationships with Han Chinese and geographically close Guizhou Miao.

Forensic characterization and genetic polymorphisms of 19 X-chromosomal STRs in 1344 Han Chinese individuals and comprehensive population relationship analyses among 20 Chinese groups

X-chromosomal short tandem repeats (X-STRs) may assist resolution of complex forensic kinship cases and complement autosomal and Y-chromosomal STRs in routine forensic practice and population genetics. In the present study, we investigated the allele/haplotype diversity and forensic genetic characteristics of 19 X- STRs in 206 Guizhou Han and 1344 Meta-Han Chinese individuals using AGCU X19 PCR amplification system. Population relationships within five Han Chinese population groups (1344 individuals), between Guizhou Han and other 19 Chinese reference populations belonging to four language families (5074 individuals), as well as between Meta-Han Chinese and other 15 minorities (3730 individuals) were performed using Reynolds’s, Nei’s and Fst genetic distances, principal component analysis (PCA), multidimensional scaling (MDS), Structure and Neighbor-Joining tree. Mean paternity exclusion chance (MEC) in Duos > 0.99999999453588 and in trios > 0.99999999999781, as well as power of discrimination (PD) > 0.99999999999980 in Guizhou Han on the basis of allele frequencies. Consistent high MECs and PDs can be observed in Meta-Han Chinese population based on both allele diversities of 19 markers and haplotype diversities of seven linkage groups (LG). DXS10135 and LG1 are the most informative and polymorphic in Han Chinese group. The comprehensive population comparisons reveal that Han Chinese is a homogenous population and has the genetically closer relationship with Hmong-Mien-speaking groups than Tibetan-Burman-speaking and Turkic-speaking populations. In summary, AGCU X19 PCR amplification system is highly polymorphic and informative in Guizhou Han and Han Chinese populations. The comprehensive population data from 20 Chinese populations analyzed in this study may be used as a reference Chinese frequency database of X-STRs for forensic casework applications.

Genetic portrait and phylogenetic analysis of an Aksu Uyghur population based on the 19 X-STR system

The X chromosome has a special mode of inheritance, and is thus a rich resource for population studies. In this study, the allele frequencies and forensic statistics of the 19 X chromosomal short tandem repeat loci were evaluated in 500 Uyghur individuals from Aksu Prefecture in northwest China. We further aimed to study whether the Uyghur populations located in various regions of Xinjiang share similar allele and haplotype frequency distributions, as they have experienced genetic exchanges. Population comparisons, PCA and MDS were performed for the Uyghurs and 27 populations and the results indicate that the Uyghur minority in Aksu has a relatively close phylogenetic relationship with East Asians, especially the Kazakh minority.

Genetic polymorphisms for 19 X-STR loci of Sichuan Han ethnicity and its comparison with Chinese populations

X-chromosomal short tandem repeats (X-STRs) can be serviced as a complementary tool in forensic deficiency cases and other complicated kinship identification. To investigate the genetic variation of the western Chinese Han population, genetic polymorphisms of 19 X-STR loci (DXS8378, DXS7423, DXS10148, DXS10159, DXS10134, DXS7424, DXS10164, DXS10162, DXS7132, DXS10079, DXS6789, DXS101, DXS10103, DXS10101, HPRTB, DXS6809, DXS10075, DXS10074 and DXS10135) included in the AGCU X19 PCR amplification kit were obtained from 201 Chinese Han individuals (108 females and 93 males) residing in Sichuan province, western China. A total of 211 alleles were found from the 19 X-STR loci, and 4-22 alleles were found for each locus with the corresponding allele frequencies spanned from 0.0034 to 0.6395. The combined PDF and PDM were 0.9999999999999999999992 and 0.9999999999997, respectively. The combined MEC_Krüger, MEC_Kishida, MEC_Desmarais as well as MEC_{Desmarais Duo} were 0.999999958110254, 0.999999999996533, 0.999999999996695 and 0.999999992428394, respectively. The number of haplotypes observed in the seven linkage groups varied from 27 to 97 for 108 male individuals with the corresponding haplotype diversities spanned from 0.9424 (DXS7424-DXS101) to 0.9979 (DXS7132-DXS10079-DXS10075-DXS10074). The above-mentioned results indicated that the 19 X-STR loci and the seven linkage groups are highly polymorphic and informative in the Sichuan Han population. Results from population comparisons and phylogenetic analyses demonstrated that genetic heterogeneity widely existed between the Sichuan Han population and Xinjiang minority ethnic groups (Uyghur and Kazakh) and genetic affinity was identified in populations which possessed the same ethno-origin or close geographic origin.

X-chromosomal STR-based genetic structure of Sichuan Tibetan minority ethnicity group and its relationships to various groups

The X-chromosomal short tandem repeats (STRs) with more informative than autosomal STRs in some complicated biological relationships identification due to its specific mode of genetic transmission can be used as a complementary tool in forensic case practices. In this study, we presented the population genetic data of 19 X-STRs, consisting of DXS10174, DXS10075, DXS10079, DXS101, DXS10101, DXS10103, DXS10134, DXS10135, DXS10148, DXS10159, DXS10162, DXS10164, DXS6789, DXS6809, DXS7132, DXS7423, DXS7424, DXS8378, and HPRTB loci, in a sample of 235 individuals of Tibetan nationality from Sichuan province, Southwest China. All 19 X-STR loci were consistent with Hardy-Weinberg equilibrium. The results showed that the combined power of discrimination in females and males are 0.999999999999999999997 and 0.9999999999997, respectively. In addition, the mean paternity exclusion chances based on the formula of MEC_Krüger, MEC_Kishida, and MEC_Desmarais as well as MEC_{Desmarais Duo} are 0.99999991, 0.9999999999924, 0.9999999999929, and 0.999999985, respectively. In summary, our findings suggested that the AGCU X19 kit can be considered to serve as a high polymorphic information tool for forensic identification and kinship testing in the Sichuan Tibetan population. Furthermore, population genetic structure investigation between Sichuan Tibetan population and other 19 populations using PCA, MDS, and phylogenetic tree illustrated that significant genetic difference was observed between the Sichuan Tibetan and Malay, as well as the Xinjiang Uyghur population.

Chinese Xibe population genetic composition according to linkage groups of X-chromosomal STRs: population genetic variability and interpopulation comparisons

BACKGROUND

The Xibe population is one of China's officially recognised populations and is now distributed separately from west to east in the northern part of China. X-chromosomal short tandem repeats have a special inheritance pattern, and could be used as complements in forensic application, especially for complex or deficiency cases.

SUBJECTS AND METHODS

This study obtained the allelic and haplotypic frequencies of 19 X-STR loci in the Xibe population from Xinjiang Uygur Autonomous Region, China, and studied the genetic differentiations between the Xibe and other populations.

RESULTS

The combined power of discrimination in females and males and mean exclusion chances in deficiency cases, normal trios and duo cases was at least 0.999 999 994. In the haplotypic study, the Xibe population showed a more similar pattern of haplotype distribution with Asian populations than populations from other continents, while allelic study also indicated a closer relationship between the Xibe and Asian populations.

CONCLUSIONS

The 19 X-STR loci would be useful in forensic application in the studied population. The Xibe population showed a closer genetic relationship with Asian populations in the study, and more population data would be necessary for more detailed genetic relationship studies.

Forensic characteristics and phylogenetic analyses of the Chinese Yi population via 19 X-chromosomal STR loci

The demographic characteristics and genetic polymorphism data of 56 Chinese nationalities or 31 administrative divisions in Chinese mainland have repeatedly been the genetic research hotspots. While most genetic studies focused on some particular Chinese populations based on autosomal or Y-chromosomal genetic markers, the forensic characteristics and phylogenetic analyses of the seventh largest Chinese population (Yi ethnicity) on the X-chromosomal genetic markers are scarce. Here, allele frequencies and forensic statistical parameters for 19 X-chromosomal short tandem repeat loci (DXS7424-DXS101, DXS6789-DXS6809, DXS7423-DXS10134, DXS10103-HPRTB-DXS10101, DXS10159-DXS10162-DXS10164, DXS10148-DXS10135-DXS8378, and DXS7132-DXS10079-DXS10074-DXS10075) of 331 Chinese Yi individuals were obtained. All 19 X-chromosomal short tandem repeat (STR) loci in females were consistent with the Hardy-Weinberg equilibrium test. A total of 214 alleles were identified with the corresponding allele frequencies spanned from 0.0019 to 0.6106. The combined PE, PDF, and PDM were 0.9999999214, 0.9999999999999999999993, and 0.9999999999998, respectively. The high combined MEC_Krüger, MEC_Kishida, MEC_Desmarais, and MEC_{Desmarais Duo} were achieved as 0.9999999617638, 0.9999999999971, 0.9999999999971, and 0.9999999931538, respectively. The findings suggested that the panel of 19 X-STR loci is highly polymorphic and informative in the Yi ethnic population and can be considered to be a powerful tool in forensic complex kinship identification. Population differentiation analyses among 12 populations indicated that significant differences in genetic structure were observed in between the Yi ethnicity and the Chinese Uyghur as well as Kazakh, and genetic homogeneity existed in similar ethno-origin or geographic origin populations.

Allele and haplotype diversity of new multiplex of 19 ChrX-STR loci in Han population from Guanzhong region (China)

X-chromosomal short tandem repeats (X-STRs) have been proved to be useful for some deficiency paternity cases in recent years. Here, we studied the genetic polymorphisms of 19 X-STR loci (DXS10148-DXS10135-DXS8378, DXS10159-DXS10162-DXS10164, DXS7132-DXS10079-DXS10074-DXS10075, DXS6809-DXS6789, DXS7424-DXS101, DXS10103-HPRTB-DXS10101 and DXS7423-DXS10134) in 252 male and 222 female individuals from Guanzhong Han population, China. No deviation for all 19 loci was observed from the Hardy-Weinberg equilibrium. The polymorphism information content values of the panel of 19 loci were more than 0.5 with the exception of the locus DXS7423. The combined power of discrimination were 0.9999999999999999999994340 in females and 0.9999999999997662 in males, respectively; and the combined mean exclusion chances were 0.999999993764 in duos and 0.999999999997444 in trios, respectively. The haplotype diversities for all the seven clusters of linked loci were more than 0.9. The results showed that the panel of 19 X-STR loci were powerful for forensic applications in Guanzhong Han population. Locus by locus population comparisons showed significant differences at more than seven loci between Guanzhong Han population and the groups from North America, Europe and Africa.