Mitochondrial and Y-chromosomal profile of the Kazakh population from East Kazakhstan

Genetic polymorphism of 27 Y-STR loci in Kazakh populations from Eastern Kazakhstan

BACKGROUND

The establishment of a national haplotype database is important for forensic and genetic applications and requires studying genetic polymorphisms at Y-STR sites. However, the genetic structure of the Eastern Kazakhstan population is poorly characterised.

AIM

To investigate the genetic polymorphisms of 27 Y-STR loci in the Kazakh population from Eastern Kazakhstan and analyse the population genetic relationships of the Eastern Kazakhs with other populations.

SUBJECTS AND METHODS

The Yfiler Plus kit was utilised to genotype 246 healthy, unrelated males from Eastern Kazakhstan. Based on the raw data, haplotype and allele frequencies along with forensic parameters were calculated, and an MDS plot was constructed.

RESULTS

A total of 207 haplotypes were detected, of which 186 were unique. The haplotype diversity and discrimination capacity were 0.997 and 0.841, respectively. Population comparisons showed that Eastern Kazakhs have close genetic relationships with Kazakhs from Xinjiang, China. At the same time, a difference was found between the studied population and the previous one in the same part of Kazakhstan.

CONCLUSIONS

The obtained haplotypes will help to expand the Kazakhstan Y-chromosome reference database and will be useful for future genetic research and forensic applications.

Kazak mitochondrial genomes provide insights into the human population history of Central Eurasia

As a historical nomadic group in Central Asia, Kazaks have mainly inhabited the steppe zone from the Altay Mountains in the East to the Caspian Sea in the West. Fine scale characterization of the genetic profile and population structure of Kazaks would be invaluable for understanding their population history and modeling prehistoric human expansions across the Eurasian steppes. With this mind, we characterized the maternal lineages of 200 Kazaks from Jetisuu at mitochondrial genome level. Our results reveal that Jetisuu Kazaks have unique mtDNA haplotypes including those belonging to the basal branches of both West Eurasian (R0, H, HV) and East Eurasian (A, B, C, D) lineages. The great diversity observed in their maternal lineages may reflect pivotal geographic location of Kazaks in Eurasia and implies a complex history for this population. Comparative analyses of mitochondrial genomes of human populations in Central Eurasia reveal a common maternal genetic ancestry for Turko-Mongolian speakers and their expansion being responsible for the presence of East Eurasian maternal lineages in Central Eurasia. Our analyses further indicate maternal genetic affinity between the Sherpas from the Tibetan Plateau with the Turko-Mongolian speakers.

Whole-Genome Sequencing and Genomic Variant Analysis of Kazakh Individuals

Kazakhstan, the ninth-largest country in the world, is located along the Great Silk Road and connects Europe with Asia. Historically, its territory has been inhabited by nomadic tribes, and modern-day Kazakhstan is a multiethnic country with a dominant Kazakh population. We sequenced and analyzed the genomes of five ethnic Kazakhs at high coverage using the Illumina HiSeq2000 next-generation sequencing platform. The five Kazakhs yielded a total number of base pairs ranging from 87,308,581,400 to 107,526,741,301. On average, 99.06% were properly mapped. Based on the Het/Hom and Ti/Tv ratios, the quality of the genomic data ranged from 1.35 to 1.49 and from 2.07 to 2.08, respectively. Genetic variants were identified and annotated. Functional analysis of the genetic variants identified several variants that were associated with higher risks of metabolic and neurogenerative diseases. The present study showed high levels of genetic admixture of Kazakhs that were comparable to those of other Central Asians. These whole-genome sequence data of healthy Kazakhs could contribute significantly to biomedical studies of common diseases as their findings could allow better insight into the genotype–phenotype relations at the population level.

Genetic polymorphism of 27 Y-STR loci in Kazakh populations from Northern Kazakhstan

BACKGROUND

Previous studies of the genetic polymorphism of the Y-chromosome of Kazakhs were focused on the Eastern, Central, Southern, and Western regions of Kazakhstan. In addition, many of these studies were limited to 17 Y-STR loci from the Yfiler.

AIM

To enrich the existing Kazakhstan Y-chromosome Haplotype Reference Database from the Northern Kazakh population data by a wide set of 27 Y-STR and investigate the population genetic relationships with previously published data.

SUBJECTS AND METHODS

27 Y-STR loci from the Yfiler Plus PCR Amplification Kit were analysed in 382 healthy unrelated Kazakh males from Northern Kazakhstan. Genetic polymorphism was analysed using Arlequin software.

RESULTS

A total of 326 distinct haplotypes of the 27 Y-STR loci were observed in 382 individuals. The discrimination capacity (0.9982) and haplotype diversity (0.8534) were computed. A total of 168 alleles at single-copy loci were observed, and their frequencies ranged from 0.003 to 0.843. The pairwise genetic distance (R_ST) showed that the Northern Kazakh population is genetically distinct from the Chinese Kazakh population.

CONCLUSIONS

Genetic polymorphism shows that the potential value of 27 Y-STR loci for forensic casework in the Northern Kazakh population, and the current findings, might be beneficial for paternal lineages in the study of population genetics.

Genetic Relationship Among the Kazakh People Based on Y-STR Markers Reveals Evidence of Genetic Variation Among Tribes and Zhuz

Ethnogenesis of Kazakhs took place in Central Asia, a region of high genetic and cultural diversity. Even though archaeological and historical studies have shed some light on the formation of modern Kazakhs, the process of establishment of hierarchical socioeconomic structure in the Steppe remains contentious. In this study, we analyzed haplotype variation at 15 Y-chromosomal short-tandem-repeats obtained from 1171 individuals from 24 tribes representing the three socio-territorial subdivisions (Senior, Middle and Junior zhuz) in Kazakhstan to comprehensively characterize the patrilineal genetic architecture of the Kazakh Steppe. In total, 577 distinct haplotypes were identified belonging to one of 20 haplogroups; 16 predominant haplogroups were confirmed by SNP-genotyping. The haplogroup distribution was skewed towards C2-M217, present in all tribes at a global frequency of 51.9%. Despite signatures of spatial differences in haplotype frequencies, a Mantel test failed to detect a statistically significant correlation between genetic and geographic distance between individuals. An analysis of molecular variance found that ∼8.9% of the genetic variance among individuals was attributable to differences among zhuzes and ∼20% to differences among tribes within zhuzes. The STRUCTURE analysis of the 1164 individuals indicated the presence of 20 ancestral groups and a complex three-subclade organization of the C2-M217 haplogroup in Kazakhs, a result supported by the multidimensional scaling analysis. Additionally, while the majority of the haplotypes and tribes overlapped, a distinct cluster of the O2 haplogroup, mostly of the Naiman tribe, was observed. Thus, firstly, our analysis indicated that the majority of Kazakh tribes share deep heterogeneous patrilineal ancestries, while a smaller fraction of them are descendants of a founder paternal ancestor. Secondly, we observed a high frequency of the C2-M217 haplogroups along the southern border of Kazakhstan, broadly corresponding to both the path of the Mongolian invasion and the ancient Silk Road. Interestingly, we detected three subclades of the C2-M217 haplogroup that broadly exhibits zhuz-specific clustering. Further study of Kazakh haplotypes variation within a Central Asian context is required to untwist this complex process of ethnogenesis.

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.

Association of polymorphisms in TP53 and the promoter region of IL10 with gastric cancer in a Kazakh population

The emerging evidence indicates that single nucleotide polymorphisms (SNPs) of the tumor necrosis factor (TNF), interleukin 10 (IL10), tumor protein p53 (TP53), and cluster of differentiation 14 (CD14) genes may determine individual susceptibility to gastric cancer (GC). We aimed to investigate the associations for polymorphisms of the TNF, IL10, TP53, and CD14 genes in a population of Kazakhs, to identify potential risk or protective associations of the SNPs with GC. A case group of 143 patients hospitalized for GC was enrolled. Controls were 355 volunteers with no history of any cancer and frequency matched with cases by age. Differences in proportions for categorical variables and the assessment of genotypic frequencies conforming to the Hardy-Weinberg equilibrium law were evaluated by the Chi-square test. Associations between genetic polymorphisms and the risk of GC were estimated by regression analysis. For genetic analysis, three genetic models (additive, dominant, and recessive) were used. Four significant associations were found. The SNPs rs1042522 of TP53 and rs1800896 of IL10 were risk factors for GC by the additive model. Two polymorphisms of IL10 were protective of GC, namely, rs1800872 by additive model and rs1800871 by recessive model. No significant associations were observed between the TNF and CD14 polymorphisms and GC. The polymorphisms TP53 rs1042522 and IL10 rs1800896 are associated with GC risk, while the polymorphisms IL10 rs1800872 and rs1800871 are protective of GC in the population of Kazakhs.

Y-chromosome evidence confirmed the Kerei-Abakh origin of Aksay Kazakhs

Aksay Kazakhs are the easternmost branch of Kazakhs, residing in Jiuquan city, the forefront of the ancient Silk Road. However, the genetic diversity of Aksay Kazakhs and its relationships with other Kazakhs still lack attention. To clarify this issue, we analyzed the non-recombining portion of the Y-chromosome from 93 Aksay Kazakhs samples, using a high-resolution analysis of 106 biallelic markers and 17 STRs. The lowest haplogroup diversity (0.38) was observed in Aksay Kazakhs among all studied Kazakh populations. The social and cultural traditions of the Kazakhs shaped their current pattern of genetic variation. Aksay Kazakhs tended to migrate with clans and had limited paternal admixture with neighboring populations. Aksay Kazakhs had the highest frequency (80%) of haplogroup C2b1a3a1-F3796 (previous C3*-Star Cluster) among the investigated Eurasian steppe populations, which was now seen as the genetic marker of Kerei clan. Furthermore, NETWORK analysis indicated that Aksay Kazakhs originated from sub-clan Kerei-Abakh in Kazakhstan with DYS448 = 23. TMRCA estimates of three recent descent clusters detected in C2*-M217 (xM48) network, one of which incorporate nearly all of the C2b1a3a1-F3796 Aksay Kazakhs samples, gave the age range of 976-1405 YA for DC1, 1059-1314 YA for DC2, and 1139-1317 YA for DC3, respectively; this is coherent with the 7^th to the 11^th centuries Altaic-speaking pastoral nomadic population expansion.

Decoding a highly mixed Kazakh genome

We provide a Kazakh whole genome sequence (MJS) and analyses with the largest comparative Kazakh genomic data available to date. We found 102,240 novel SNVs and a high level of heterozygosity. ADMIXTURE analysis confirmed a significant proportion of variations in this individual coming from all continents except Africa and Oceania. A principal component analysis showed neighboring Kalmyk, Uzbek, and Kyrgyz populations to have the strongest resemblance to the MJS genome which reflects fairly recent Kazakh history. MJS's mitochondrial haplogroup, J1c2, probably represents an early European and Near Eastern influence to Central Asia. This was also supported by the heterozygous SNPs associated with European phenotypic features and strikingly similar Kazakh ancestral composition inferred by ADMIXTURE. Admixture (f3) analysis showed that MJS's genomic signature is best described as a cross between the Neolithic East Asian (Devil's Gate1) and the Bronze Age European (Halberstadt_LBA1) components rather than a contemporary admixture.

Type 2 diabetes mellitus: distribution of genetic markers in Kazakh population

Background

Ethnic differences exist in the frequencies of genetic variations that contribute to the risk of common disease. This study aimed to analyse the distribution of several genes, previously associated with susceptibility to type 2 diabetes and obesity-related phenotypes, in a Kazakh population.

Methods

A total of 966 individuals belonging to the Kazakh ethnicity were recruited from an outpatient clinic. We genotyped 41 common single nucleotide polymorphisms (SNPs) previously associated with type 2 diabetes in other ethnic groups and 31 of these were in Hardy–Weinberg equilibrium. The obtained allele frequencies were further compared to publicly available data from other ethnic populations. Allele frequencies for other (compared) populations were pooled from the haplotype map (HapMap) database. Principal component analysis (PCA), cluster analysis, and multidimensional scaling (MDS) were used for the analysis of genetic relationship between the populations.

Results

Comparative analysis of allele frequencies of the studied SNPs showed significant differentiation among the studied populations. The Kazakh population was grouped with Asian populations according to the cluster analysis and with the Caucasian populations according to PCA. According to MDS, results of the current study show that the Kazakh population holds an intermediate position between Caucasian and Asian populations.

Conclusion

A high percentage of population differentiation was observed between Kazakh and world populations. The Kazakh population was clustered with Caucasian populations, and this result may indicate a significant Caucasian component in the Kazakh gene pool.

The Connection of the Genetic, Cultural and Geographic Landscapes of Transoxiana

We have analyzed Y-chromosomal variation in populations from Transoxiana, a historical region covering the southwestern part of Central Asia. We studied 780 samples from 10 regional populations of Kazakhs, Uzbeks, Turkmens, Dungans, and Karakalpaks using 35 SNP and 17 STR markers. Analysis of haplogroup frequencies using multidimensional scaling and principal component plots, supported by an analysis of molecular variance, showed that the geographic landscape of Transoxiana, despite its distinctiveness and diversity (deserts, fertile river basins, foothills and plains) had no strong influence on the genetic landscape. The main factor structuring the gene pool was the mode of subsistence: settled agriculture or nomadic pastoralism. Investigation of STR-based clusters of haplotypes and their ages revealed that cultural and demic expansions of Transoxiana were not closely connected with each other. The Arab cultural expansion introduced Islam to the region but did not leave a significant mark on the pool of paternal lineages. The Mongol expansion, in contrast, had enormous demic success, but did not impact cultural elements like language and religion. The genealogy of Muslim missionaries within the settled agricultural communities of Transoxiana was based on spiritual succession passed from teacher to disciple. However, among Transoxianan nomads, spiritual and biological succession became merged.

Analysis of genetic admixture in Uyghur using the 26 Y-STR loci system

The Uyghur population has experienced extensive interaction with European and Eastern Asian populations historically. A set of high-resolution genetic markers could be useful to infer the genetic relationships between the Uyghur population and European and Asian populations. In this study we typed 100 unrelated Uyghur males living in southern Xinjiang at 26 Y-STR loci. Using the high-resolution 26 Y-STR loci system, we investigated genetic and phylogenetic relationship between the Uyghur population and 23 reference European or Asian populations. We found that the Uyghur population exhibited a genetic admixture of Eastern Asian and European populations, and had a slightly closer relationship with the selected European populations than the Eastern Asian populations. We also demonstrated that the 26 Y-STR loci system was potentially useful in forensic sciences because it has a large power of discrimination and rarely exhibits common haplotypes. However, ancestry inference of Uyghur samples could be challenging due to the admixed nature of the population.

Polymorphisms in genes involved in the absorption, distribution, metabolism, and excretion of drugs in the Kazakhs of Kazakhstan

BACKGROUND

Studies of genes involved in the absorption, distribution, metabolism, and excretion (ADME) of drugs are crucial to the development of therapeutics in clinical medicine. Such data provide information that may improve our understanding of individual differences in sensitivity or resistance to certain drugs, thereby helping to avoid adverse drug reactions (ADRs) in patients and improve the quality of therapies. Here, we aimed to analyse single nucleotide polymorphisms (SNPs) involved in the ADME of multiple drugs in Kazakhs from Kazakhstan.

RESULTS

A total of 158 SNPs involved in the ADME of various drugs were studied. We analysed 320 Kazakh DNA samples using OpenArray genotyping. Of the 158 SNPs, 75 were not found in heterozygous or homozygous variants. Comparative analysis among Kazakhs and world populations showed a fairly high percentage of population differentiation.

CONCLUSION

These results provide further information for pharmacogenetic databases and may contribute to the development of personalized approaches and safer therapies for the Kazakh population. Moreover, these data provide insights into the different racial groups that may have contributed to the Kazakh population.