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

Population dataset for 23 Y-STR in the Merkit clan form Kazakh population

This study presents a comprehensive analysis of 23 Y-STR data for the Merkit clan, a subgroup within the Kerey tribe of the Kazakh people. A total of 64 complete haplotypes were generated using the PowerPlex Y23 System. The data obtained using 23 Y-STR markers has been submitted to the Y Chromosome Haplotype Reference Database (YHRD) at yhrd.org, which will significantly enhance the forensic database for the Kazakh population in Kazakhstan. The research focuses on the distribution of haplotypes within the clan and their genealogical lines, which were visualized using a Median-joining network and Multidimensional scaling plot. The study identifies four distinct haplogroup clusters, revealing important insights into the genetic makeup and historical lineage of the Merkits. This dataset not only enriches our understanding of Kazakh genetic structure but also holds significant value for anthropological and population genetic research, as well as for forensic genetics. This work bridges a notable gap in genetic research on the Merkit clan, contributing to a deeper understanding of Central Asian nomadic tribes.

Genetic polymorphism of Y-chromosome in Kazakh populations from Southern Kazakhstan

BACKGROUND

The Kazakhs are one of the biggest Turkic-speaking ethnic groups, controlling vast swaths of land from the Altai to the Caspian Sea. In terms of area, Kazakhstan is ranked ninth in the world. Northern, Eastern, and Western Kazakhstan have already been studied in relation to genetic polymorphism 27 Y-STR. However, current information on the genetic polymorphism of the Y-chromosome of Southern Kazakhstan is limited only by 17 Y-STR and no geographical study of other regions has been studied at this variation.

RESULTS

The Kazakhstan Y-chromosome Haplotype Reference Database was expanded with 468 Kazakh males from the Zhambyl and Turkestan regions of South Kazakhstan by having their 27 Y-STR loci and 23 Y-SNP markers analyzed. Discrimination capacity (DC = 91.23%), haplotype match probability (HPM = 0.0029) and haplotype diversity (HD = 0.9992) are defined. Most of this Y-chromosome variability is attributed to haplogroups C2a1a1b1-F1756 (2.1%), C2a1a2-M48 (7.3%), C2a1a3-F1918 (33.3%) and C2b1a1a1a-M407 (6%). Median-joining network analysis was applied to understand the relationship between the haplotypes of the three regions. In three genetic layer can be described the position of the populations of the Southern region of Kazakhstan-the geographic Kazakh populations of Kazakhstan, the Kazakh tribal groups, and the people of bordering Asia.

CONCLUSION

The Kazakhstan Y-chromosome Haplotype Reference Database was formed for 27 Y-STR loci with a total sample of 1796 samples of Kazakhs from 16 regions of Kazakhstan. The variability of the Y-chromosome of the Kazakhs in a geographical context can be divided into four main clusters-south, north, east, west. At the same time, in the genetic space of tribal groups, the population of southern Kazakhs clusters with tribes from the same region, and genetic proximity is determined with the populations of the Hazaras of Afghanistan and the Mongols of China.

Ancient Components and Recent Expansion in the Eurasian Heartland: Insights into the Revised Phylogeny of Y-Chromosomes from Central Asia

In the past two decades, studies of Y chromosomal single nucleotide polymorphisms (Y-SNPs) and short tandem repeats (Y-STRs) have shed light on the demographic history of Central Asia, the heartland of Eurasia. However, complex patterns of migration and admixture have complicated population genetic studies in Central Asia. Here, we sequenced and analyzed the Y-chromosomes of 187 male individuals from Kazakh, Kyrgyz, Uzbek, Karakalpak, Hazara, Karluk, Tajik, Uyghur, Dungan, and Turkmen populations. High diversity and admixture from peripheral areas of Eurasia were observed among the paternal gene pool of these populations. This general pattern can be largely attributed to the activities of ancient people in four periods, including the Neolithic farmers, Indo-Europeans, Turks, and Mongols. Most importantly, we detected the consistent expansion of many minor lineages over the past thousand years, which may correspond directly to the formation of modern populations in these regions. The newly discovered sub-lineages and variants provide a basis for further studies of the contributions of minor lineages to the formation of modern populations in Central Asia.

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 continuity of Indo-Iranian speakers since the Iron Age in southern Central Asia

Since prehistoric times, southern Central Asia has been at the crossroads of the movement of people, culture, and goods. Today, the Central Asian populations are divided into two cultural and linguistic groups: the Indo-Iranian and the Turko-Mongolian groups. Previous genetic studies unveiled that migrations from East Asia contributed to the spread of Turko-Mongolian populations in Central Asia and the partial replacement of the Indo-Iranian populations. However, little is known about the origin of the latters. To shed light on this, we compare the genetic data on two current-day Indo-Iranian populations — Yaghnobis and Tajiks — with genome-wide data from published ancient individuals. The present Indo-Iranian populations from Central Asia display a strong genetic continuity with Iron Age samples from Turkmenistan and Tajikistan. We model Yaghnobis as a mixture of 93% Iron Age individual from Turkmenistan and 7% from Baikal. For the Tajiks, we observe a higher Baikal ancestry and an additional admixture event with a South Asian population. Our results, therefore, suggest that in addition to a complex history, Central Asia shows a remarkable genetic continuity since the Iron Age, with only limited gene flow.

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.

Dual origins of the Northwest Chinese Kyrgyz: the admixture of Bronze age Siberian and Medieval Niru'un Mongolian Y chromosomes

The Kyrgyz are a trans-border ethnic group, mainly living in Kyrgyzstan. Previous genetic investigations of Central Asian populations have repeatedly investigated the Central Asian Kyrgyz. However, from the standpoint of human evolution and genetic diversity, Northwest Chinese Kyrgyz is one of the more poorly studied populations. In this study, we analyzed the non-recombining portion of the Y-chromosome from 298 male Kyrgyz samples from Xinjiang Uygur Autonomous Region in northwestern China, using a high-resolution analysis of 108 biallelic markers and 17 or 24 STRs. First, via a Y-SNP-based PCA plot, Northwest Chinese Kyrgyz tended to cluster with other Kyrgyz population and are located in the West Asian and Central Asian group. Second, we found that the Northwest Chinese Kyrgyz display a high proportion of Y-lineage R1a1a1b2a2a-Z2125, related to Bronze Age Siberian, and followed by Y-lineage C2b1a3a1-F3796, related to Medieval Niru'un Mongols, such as Uissun tribe from Kazakhs. In these two dominant lineages, two unique recent descent clusters have been detected via NETWORK analysis, respectively, but they have nearly the same TMRCA ages (about 13th-14th centuries). This finding once again shows that the expansions of Mongol Empire had a striking effect on the Central Asian gene pool.

Medieval Super-Grandfather founder of Western Kazakh Clans from Haplogroup C2a1a2-M48

Western Kazakhstan is populated by three clans totaling 2 million people. Since the clans are patrilineal, the Y-chromosome is the most informative genetic system for tracing their origin. We genotyped 40 Y-SNP and 17 Y-STR markers in 330 Western Kazakhs. High phylogenetic resolution within haplogroup C2a1a2-M48 was achieved by using additional SNPs. Three lines of evidence indicate that the Alimuly and Baiuly clans (but not the Zhetiru clan) have a common founder placed 700 ± 200 years back by the STR data and 500 ± 200 years back by the sequencing data. This supports traditional genealogy claims about the descent of these clans from Emir Alau, who lived 650 years ago and whose lineage might be carried by two-thirds of Western Kazakhs. There is accumulation of specific haplogroups in the subclans representing other lineages, confirming that the clan structure corresponds with the paternal genetic structure of the steppe population.

The medieval Mongolian roots of Y-chromosomal lineages from South Kazakhstan

Background

The majority of the Kazakhs from South Kazakhstan belongs to the 12 clans of the Senior Zhuz. According to traditional genealogy, nine of these clans have a common ancestor and constitute the Uissun tribe. There are three main hypotheses of the clans’ origin, namely, origin from early Wusuns, from Niru’un Mongols, or from Darligin Mongols. We genotyped 490 samples of South Kazakhs by 35 Y-chromosomal SNPs (single nucleotide polymorphism) and 17 STRs (short tandem repeat). Additionally, 133 samples from citizen science projects were included into the study.

Results

We found that three Uissun clans have unique Y-chromosomal profiles, but the remaining six Uissun clans and one non-Uissun clan share a common paternal gene pool. They share a high frequency (> 40%) of the C2*-ST haplogroup (marked by the SNP F3796), which is associated with the early Niru’un Mongols. Phylogenetic analysis of this haplogroup carried out on 743 individuals from 25 populations of Eurasia has revealed a set of haplotype clusters, three of which contain the Uissun haplotypes. The demographic expansion of these clusters dates back to the 13-fourteenth century, coinciding with the time of the Uissun’s ancestor Maiky-biy known from historical sources. In addition, it coincides with the expansion period of the Mongol Empire in the Late Middle Ages. A comparison of the results with published aDNA (ancient deoxyribonucleic acid) data and modern Y haplogroups frequencies suggest an origin of Uissuns from Niru’un Mongols rather than from Wusuns or Darligin Mongols.

Conclusions

The Y-chromosomal variation in South Kazakh clans indicates their common origin in 13th–14th centuries AD, in agreement with the traditional genealogy. Though genetically there were at least three ancestral lineages instead of the traditional single ancestor. The majority of the Y-chromosomal lineages of South Kazakhstan was brought by the migration of the population related to the medieval Niru’un Mongols.

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.

Rectifying long-standing misconceptions about the ρ statistic for molecular dating

When divided by a given mutation rate, the ρ (rho) statistic provides a simple estimator of the age of a clade within a phylogenetic tree by averaging the number of mutations from each sample in the clade to its root. However, a long-standing critique of the use of ρ in genetic dating has been quite often cited. Here we show that the critique is unfounded. We demonstrate by a formal mathematical argument and illustrate with a simulation study that ρ estimates are unbiased and also that ρ and maximum likelihood estimates do not differ in any systematic fashion. We also demonstrate that the claim that the associated confidence intervals commonly estimate the uncertainty inappropriately is flawed since it relies on a means of calculating standard errors that is not used by any other researchers, whereas an established expression for the standard error is largely unproblematic. We conclude that ρ dating, alongside approaches such as maximum likelihood (ML) and Bayesian inference, remains a useful tool for genetic dating.

Reconstructing the genetic structure of the Kazakh from clan distribution data

Applying quasigenetic markers - non-biological traits which are nevertheless inherited in generations - is one of the research fields within human population genetics. For the West European, East European, and Caucasus populations, surnames are typical quasigenetic markers. For Central Asian populations, particularly Kazakh, the clan affiliation serves as a good marker: a set of papers demonstrated that many clans include mainly persons which biologically descent from a recent common ancestor. In this study, we analyzed a large (~4.2 million persons) dataset on quasigenetic markers - the geographic distribution of 50 Kazakh clans at the beginning of the 20th century, and compared the dataset with the direct data of the Y-chro-mosomal diversity in modern Kazakh populations. The analysis included three steps: the isonymy method, which is standard for quasigenetic markers, comparing frequencies of quasigenetic markers, and comparing the quasigenetic and genetic datasets. We constructed 50 maps of frequency of the distribution of each clan and revealed that these maps correlate with the maps of genetic distances. The Mantel test also demonstrated a significant correlation between geographic and quasigenetic distances (г = 0.60; p < 0.05). The analysis of inter-population variability revealed the largest diversity between geographic territories corresponding to the social-territorial groups of the Kazakh Khanate (zhuzes) rather than to other historical groups that existed on the territory of Kazakhstan in preceding and modern epochs. The same is evidenced by the principal components and multidimensional scaling plots, which grouped geographic populations into three clusters corresponding to three zhuzes. This indicates that the final structuring of the Kazakh gene pool might have occurred during the Kazakh Khanate period.

Match probabilities for Y-chromosomal profiles: A paradigm shift

Calculating match probabilities for genetic profiles under the hypothesis that a person of interest (henceforth the 'suspect') is not the donor of a particular forensic trace is challenging because the reference population is usually not clear-defined in such cases. Hence, the concept of 'suspect population' was introduced to allow for the fact that possible alternative trace donors often resemble the suspect in terms of their geographic, ethnic and social affiliation. In fact, they may even be genetically related to the suspect. Although the possibility of relatedness affects the size of the match probability in general, this is not a practically relevant issue for autosomal profiles owing to the stochastic independence of the markers included. The situation is, however, different for Y-chromosomal short tandem repeat (STR) profiles. Here, almost all profile matches are likely to be identical by descent, and profile identity may be common even among distantly related males. The degree of relatedness between suspect and alternative trace donors is thus a critical aspect of the evaluation of Y-chromosomal STR profile matches. All methods hitherto proposed to derive match probabilities for such cases, including our own, were anti-conservative in that they equated the suspect population to a database population (of virtually unrelated individuals). The nature of the true suspect population, however, is usually unknown and hard, if not impossible, to determine so that calculation of proper match probabilities remains a difficult task. Therefore, since lower Y-chromosomal match probabilities would result from higher mutation rates, even for close relatives, future research should rather focus upon the characterization of novel and more mutable Y-chromosomal STRs.

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.

A glimpse at the intricate mosaic of ethnicities from Mesopotamia: Paternal lineages of the Northern Iraqi Arabs, Kurds, Syriacs, Turkmens and Yazidis

Widely considered as one of the cradles of human civilization, Mesopotamia is largely situated in the Republic of Iraq, which is also the birthplace of the Sumerian, Akkadian, Assyrian and Babylonian civilizations. These lands were subsequently ruled by the Persians, Greeks, Romans, Arabs, Mongolians, Ottomans and finally British prior to the independence. As a direct consequence of this rich history, the contemporary Iraqi population comprises a true mosaic of different ethnicities, which includes Arabs, Kurds, Turkmens, Assyrians, and Yazidis among others. As such, the genetics of the contemporary Iraqi populations are of anthropological and forensic interest. In an effort to contribute to a better understanding of the genetic basis of this ethnic diversity, a total of 500 samples were collected from Northern Iraqi volunteers belonging to five major ethnic groups, namely: Arabs (n = 102), Kurds (n = 104), Turkmens (n = 102), Yazidis (n = 106) and Syriacs (n = 86). 17-loci Y-STR analyses were carried out using the AmpFlSTR Yfiler system, and subsequently in silico haplogroup assignments were made to gain insights from a molecular anthropology perspective. Systematic comparisons of the paternal lineages of these five Northern Iraqi ethnic groups, not only among themselves but also in the context of the larger genetic landscape of the Near East and beyond, were then made through the use of two different genetic distance metric measures and the associated data visualization methods. Taken together, results from the current study suggested the presence of intricate Y-chromosomal lineage patterns among the five ethic groups analyzed, wherein both interconnectivity and independent microvariation were observed in parallel, albeit in a differential manner. Notably, the novel Y-STR data on Turkmens, Syriacs and Yazidis from Northern Iraq constitute the first of its kind in the literature. Data presented herein is expected to contribute to further population and forensic investigations in Northern Iraq in particular and the Near East in general.