A perspective on the history of the Iberian gypsies provided by phylogeographic analysis of Y-chromosome lineages

Development and validation of YARN: A novel SE-400 MPS kit for East Asian paternal lineage analysis

Y-chromosomal short tandem repeat polymorphisms (Y-STRs) and Y-chromosomal single nucleotide polymorphisms (Y-SNPs) are valuable genetic markers used in paternal lineage identification and population genetics. Currently, there is a lack of an effective panel that integrates Y-STRs and Y-SNPs for studying paternal lineages, particularly in East Asian populations. Hence, we developed a novel Y-chromosomal targeted panel called YARN (Y-chromosome Ancestry and Region Network) based on multiplex PCR and a single-end 400 massive parallel sequencing (MPS) strategy, consisting of 44 patrilineage Y-STRs and 260 evolutionary Y-SNPs. A total of 386 reactions were validated for the effectiveness and applicability of YARN according to SWGDAM validation guidelines, including sensitivity (with a minimum input gDNA of 0.125 ng), mixture identification (ranging from 1:1-1:10), PCR inhibitor testing (using substances such as 50 μM hematin, 100 μM hemoglobin, 100 μM humic acid, and 2.5 mM indigo dye), species specificity (successfully distinguishing humans from other animals), repeatability study (achieved 100% accuracy), and concordance study (with 99.91% accuracy for 1121 Y-STR alleles). Furthermore, we conducted a pilot study using YARN in a cohort of 484 Han Chinese males from Huaiji County, Zhaoqing City, Guangdong, China (GDZQHJ cohort). In this cohort, we identified 52 different Y-haplogroups and 73 different surnames. We found weak to moderate correlations between the Y-haplogroups, Chinese surnames, and geographical locations of the GDZQHJ cohort (with λ values ranging from 0.050 to 0.340). However, when we combined two different categories into a new independent variable, we observed stronger correlations (with λ values ranging from 0.617 to 0.754). Overall, the YARN panel, which combines Y-STR and Y-SNP genetic markers, meets forensic DNA quality assurance guidelines and holds potential for East Asian geographical origin inference and paternal lineage analysis.

Founder lineages in the Iberian Roma mitogenomes recapitulate the Roma diaspora and show the effects of demographic bottlenecks

The Roma are the largest ethnic minority in Europe. With a Northwestern Indian origin around ~ 1.5 kya, they travelled throughout West Asia until their arrival in Europe around the eleventh century CE. Their diaspora through Europe is characterized by population bottlenecks and founder events which have contributed to their present day genetic and cultural diversity. In our study, we focus on the effects of founder effects in the mitochondrial DNA (mtDNA) pool of Iberian Roma by producing and analyzing 144 novel whole mtDNA sequences of Iberian Roma. Over 60% of their mtDNA pool is composed by founder lineages of South Asian origin or acquired by gene flow during their diaspora in the Middle East or locally in Europe in Europe. The TMRCA of these lineages predates the historical record of the Roma arrival in Spain. The abundance of founder lineages is in contrast with ~ 0.7% of autochthonous founder lineages present in the non-Roma Iberian population. Within those founder lineages, we found a substantial amount of South Asian M5a1b1a1 haplotypes and high frequencies of West Eurasian founder lineages (U3b1c, J2b1c, J1c1b, J1b3a, H88, among others), which we characterized phylogenetically and put in phylogeographical context. Besides, we found no evidence of genetic substructure of Roma within the Iberian Peninsula. These results show the magnitude of founder effects in the Iberian Roma and further explain the Roma history and genetic diversity from a matrilineal point of view.

Are Roma People Descended from the Punjab Region of Pakistan: A Y-Chromosomal Perspective

Gypsies are a separate ethnic group living in Pakistan and some other countries as well. They are mostly known as ‘Roma’ and ‘untouchables’. They have different types of lifestyles as compared to other common people, as they always keep migrating from one place to another. They do not have proper houses; they live in tent houses and most probably work on daily wages to earn their living. Gypsies cannot be specified according to the place of residence and can only be classified according to their migration route. Previous historical and linguistic research showed the north Indian origin of Roma people. The present study collected 285 unrelated Roma individuals living in Punjab and typed with the Goldeneye Y20 system. Allelic frequencies ranged between 0.0035 and 0.5266, with haplotype diversity (HD) of 0.9999 and discrimination capacity (DC) of 0.8790. Gene diversity (GD) ranged from 0.6489 (DYS391) to 0.9764 (DYS391) (DY385ab). A total of 223 unique alleles were observed. Interestingly, the haplogroup R accounted for 40.56% and J for 22.06%. In MDS analysis, Pakistani Roma formed a close cluster with Roma from Constanta, Romania. The migration pattern of the Roma population from Pakistan, India and Europe was inferred using coalescence theory in the Migrate-n program. Overlapping Y-STR data were used to test different migration models. These migration models showed us the dominant gene flow from Pakistan to India and Europe to Pakistan. The results of our study showed that Y STRs provided substantially stronger discriminatory power in the Pakistani Roma population.

Paternal genetic structure of the Bosnian-Herzegovinian Roma: A Y-chromosomal STR study

OBJECTIVES

Studies indicate the complex nature of the genetic structure of the European Roma which has been shaped by different effects of their demographic history, while preserving their ancestral Indian origin. The primary aims of this study were to present for the first time the paternal profiles of the Roma from Bosnia and Herzegovina based on the data from Y-chromosome STR loci, identify the components of non-Roma paternal gene flow into the Roma, and evaluate the genetic relationships with other European Roma populations.

MATERIALS AND METHODS

In this study, 110 DNA samples of unrelated males from Roma populations residing in different regions of Bosnia and Herzegovina were genotyped using the 23 Y-STR loci included in the PowerPlex Y23 system.

RESULTS

The analysis of the genetic structure of the Bosnian-Herzegovinian Roma revealed intra-country population substructuring and indicated differing genetic affinities between the Bosnian-Herzegovinian Roma and other European Roma populations. The paternal genetic structure of the Bosnian-Herzegovinian Roma has two components: an ancestral component represented by haplogroup H1a1a-M82, and European component presented by haplogroups I1-M253, I2a1a2b-L621, J2a1a-L26, J2a1a1a2b2a3~Z7671, J2b2a-M241, G2a2b2a1a1b-L497, and E1b1b-M215.

CONCLUSION

Genetic relations between the Bosnian-Herzegovinian Roma and other European Roma are shaped by different influences on their demographic history. The data suggest that the paternal gene pool of the Roma from Bosnia and Herzegovina might be a consequence of an early separation of the proto-Roma population and the later gene flow as well as factors of the isolation that accompany the Roma populations in some Bosnian-Herzegovinian regions.

First insights into the genetics of 21-hydroxylase deficiency in the Roma population

BACKGROUND

21-hydroxylase deficiency (21OHD) is an autosomal recessive disorder with an incidence of 1:10,000-1:20,000 and is the result of various mutations in the CYP21A2 gene. 21OHD has been described in many different populations, but it has not been studied in Roma individuals so far. The aim of the study was to analyse the genotype in Roma patients with 21OHD and the prevalence of the disease in the Roma population of North Macedonia.

METHODS

Molecular analysis of the nine most frequent CYP21A2 mutations in all known Roma patients with CAH in North Macedonia, relatives and healthy individuals of Roma ancestry, using the PCR/ACRS method.

RESULTS

Ten Roma patients with 21OHD were identified, of which nine had the salt-wasting and one had the simple virilizing form. Calculated incidence of 21OHD in the North Macedonian Roma population was 1:3375. Interestingly, 9/10 patients (90%) were homozygous for the In2G splicing mutation (293-13A/C > G). Standard therapy with hydrocortisone and fludrocortisone had been introduced according to the guidelines. In 16 healthy relatives investigated for CYP21A2 mutations, heterozygosity for the In2G mutation was detected in 13/32 (40.6%) alleles. In 100 healthy Roma individuals, none related to the analysed families, no CYP21A2 mutations were detected.

CONCLUSION

The Roma population in North Macedonia had a very high incidence of classic 21OHD. Almost all patients had the severe salt-wasting form and the In2G/In2G genotype.

The Counteracting Effects of Demography on Functional Genomic Variation: The Roma Paradigm

Demographic history plays a major role in shaping the distribution of genomic variation. Yet the interaction between different demographic forces and their effects in the genomes is not fully resolved in human populations. Here, we focus on the Roma population, the largest transnational ethnic minority in Europe. They have a South Asian origin and their demographic history is characterized by recent dispersals, multiple founder events, and extensive gene flow from non-Roma groups. Through the analyses of new high-coverage whole exome sequences and genome-wide array data for 89 Iberian Roma individuals together with forward simulations, we show that founder effects have reduced their genetic diversity and proportion of rare variants, gene flow has counteracted the increase in mutational load, runs of homozygosity show ancestry-specific patterns of accumulation of deleterious homozygotes, and selection signals primarily derive from preadmixture adaptation in the Roma population sources. The present study shows how two demographic forces, bottlenecks and admixture, act in opposite directions and have long-term balancing effects on the Roma genomes. Understanding how demography and gene flow shape the genome of an admixed population provides an opportunity to elucidate how genomic variation is modeled in human populations.

Recent Common Origin, Reduced Population Size, and Marked Admixture Have Shaped European Roma Genomes

The Roma Diaspora-traditionally known as Gypsies-remains among the least explored population migratory events in historical times. It involved the migration of Roma ancestors out-of-India through the plateaus of Western Asia ultimately reaching Europe. The demographic effects of the Diaspora-bottlenecks, endogamy, and gene flow-might have left marked molecular traces in the Roma genomes. Here, we analyze the whole-genome sequence of 46 Roma individuals pertaining to four migrant groups in six European countries. Our analyses revealed a strong, early founder effect followed by a drastic reduction of ∼44% in effective population size. The Roma common ancestors split from the Punjabi population, from Northwest India, some generations before the Diaspora started, <2,000 years ago. The initial bottleneck and subsequent endogamy are revealed by the occurrence of extensive runs of homozygosity and identity-by-descent segments in all Roma populations. Furthermore, we provide evidence of gene flow from Armenian and Anatolian groups in present-day Roma, although the primary contribution to Roma gene pool comes from non-Roma Europeans, which accounts for >50% of their genomes. The linguistic and historical differentiation of Roma in migrant groups is confirmed by the differential proportion, but not a differential source, of European admixture in the Roma groups, which shows a westward cline. In the present study, we found that despite the strong admixture Roma had in their diaspora, the signature of the initial bottleneck and the subsequent endogamy is still present in Roma genomes.

European Roma groups show complex West Eurasian admixture footprints and a common South Asian genetic origin

The Roma population is the largest transnational ethnic minority in Europe, characterized by a linguistic, cultural and historical heterogeneity. Comparative linguistics and genetic studies have placed the origin of European Roma in the Northwest of India. After their migration across Persia, they entered into the Balkan Peninsula, from where they spread into Europe, arriving in the Iberian Peninsula in the 15th century. Their particular demographic history has genetic implications linked to rare and common diseases. However, the South Asian source of the proto-Roma remains still untargeted and the West Eurasian Roma component has not been yet deeply characterized. Here, in order to describe both the South Asian and West Eurasian ancestries, we analyze previously published genome-wide data of 152 European Roma and 34 new Iberian Roma samples at a fine-scale and haplotype-based level, with special focus on the Iberian Roma genetic substructure. Our results suggest that the putative origin of the proto-Roma involves a Punjabi group with low levels of West Eurasian ancestry. In addition, we have identified a complex West Eurasian component (around 65%) in the Roma, as a result of the admixture events occurred with non-proto-Roma populations between 1270–1580. Particularly, we have detected the Balkan genetic footprint in all European Roma, and the Baltic and Iberian components in the Northern and Western Roma groups, respectively. Finally, our results show genetic substructure within the Iberian Roma, with different levels of West Eurasian admixture, as a result of the complex historical events occurred in the Peninsula.

Human demographic processes and admixture events leave traceable footprints in the genomes of the populations and they can modulate the genetic architecture of complex diseases. Here, we aim to study the Roma people, an admixed population with a particular demographic history recognized as the largest ethnic minority in Europe. Previous studies suggest that they originated in South Asia 1,500 years ago and followed a diaspora towards Europe with extensive admixture with non-Roma West Eurasian groups. However, the genetic components of the Roma have not been deeply characterized. Our study reveals a common South Asian origin of all European Roma, closely related to a Punjabi group from Northwestern India. Through fine-scale haplotype-based methods, we describe a complex West Eurasian genetic component in the Roma groups, identifying a common Balkan ancestry and country-specific admixture footprints consistent with the dispersion through Europe. Our findings provide new insights into the demographic history and recent admixture events that have shaped the genetic composition of European Roma groups and could enable a better genetic characterization of complex disease in this population.

Paternal portrait of populations of the middle Magdalena River region (Tolima and Huila, Colombia): New insights on the peopling of Central America and northernmost South America

The valley of the Magdalena River is one of the main population pathways in Colombia. The gene pool and spatial configuration of human groups in this territory have been outlined throughout three historical stages: the Native pre-Hispanic world, Spanish colonization, and XIX century migrations. This research was designed with the goal of characterizing the diversity and distribution pattern of Y-chromosome lineages that are currently present in the Tolima and Huila departments (middle Magdalena River region). Historic cartography was used to identify the main geographic sites where the paternal lineages belonging to this area have gathered. Twelve municipalities were chosen, and a survey that included genealogical information was administered. Samples collected from 83 male volunteers were analyzed for 48 Y-SNPs and 17 Y-STRs. The results showed a highly diverse region characterized by the presence of 16 sublineages within the major clades R, Q, J, G, T and E and revealed that 93% (n = 77) of haplotypes were different. Among these haplogroups, European-specific R1b-M269 lineages were the most representative (57.83%), with six different subhaplogroups and 43 unique haplotypes. Native American paternal ancestry was also detected based on the presence of the Q1a2-M3*(xM19, M194, M199) and Q1a2-M346*(xM3) lineages. Interestingly, all Q1a2-M346*(xM3) samples (n = 7, with five different haplotypes) carried allele six at the DYS391 locus. This allele has a worldwide frequency of 0.169% and was recently associated with a new Native subhaplogroup. An in-depth phylogenetic analysis of these samples suggests the Tolima and Huila region to be the principal area in all Central and South America where this particular Native lineage is found. This lineage has been present in the region for at least 1,809 (+/- 0,5345) years.

Revealing the impact of the Caucasus region on the genetic legacy of Romani people from genome-wide data

Romani people are a significant minority in Europe counting about 10 million individuals scattered throughout the continent. They are a migratory group originating from Northwestern India. Their exodus from India occurred approximately 1000–1500 years ago. The migration route of the Romani people was reconstructed with the help of cultural anthropology, linguistics and historical records. Their migration made them through Central Asia, Middle East and the Caucasus region, prior to the arriving into Europe. Yet the significance of these regions, especially of the Caucasus, in Roma ancestry was a rather neglected topic. Contribution of the Caucasus and further affected regions to the ancestry of Roma was investigated based on genome-wide autosomal marker data. 158 European Roma samples and 41 populations from the Caucasus region, from Middle East, Central Asia and from South Asia were considered in our tests. Population structure and ancestry analysis algorithms were applied to investigate the relationship of Roma with these populations. Identical by descent DNA segment analyses and admixture linkage disequilibrium based tests were also applied. Our results suggest that the Caucasus region plays also a significant role in the genetic legacy of Romani people besides the main sources, Europe and South Asia, previously investigated by other population genetic studies. The Middle East and Central Asia seems slightly less important but far from negligible in connection with the sources of Roma ancestry. Our results point out that the Caucasus region and altogether the area of the Caspian and Black Seas had a significant role in the migration of Romani people towards Europe and contributed significantly to the genetic legacy of Roma rival to the European and Indian main sources.

Forensic genetic analyses in isolated populations with examples of central European Valachs and Roma

Isolated populations present a constant threat to the correctness of forensic genetic casework. In this review article we present several examples of how analyzing samples from isolated populations can bias the results of the forensic statistics and analyses. We select our examples from isolated populations from central and southeastern Europe, namely the Valachs and the European Roma. We also provide the reader with general strategies and principles to improve the laboratory practice (best practice) and reporting of samples from supposedly isolated populations. These include reporting the precise population data used for computing the forensic statistics, using the appropriate θ correction factor for calculating allele frequencies, typing ancestry informative markers in samples of unknown or uncertain ethnicity and establishing ethnic-specific forensic databases.

Y chromosome diversity in a linguistic isolate (Mirandese, NE Portugal)

OBJECTIVES

The purpose of this study was to genetically characterize the male lineages of people who speak Mirandese, an interesting case of a linguistic relict that can still be found in the municipality of Miranda do Douro, NE Portugal. This region lies within the area of the Leonese dialects, which are remnants of the Romance dialects spoken in the Kingdom of Leon currently grouped in the Astur-Leonese linguistic continuum. We intended to disclose affinities with surrounding populations, namely from Spain where the Astur-Leonese is also spoken.

METHODS

Eighty-eight unrelated males (58 from Miranda and 30 from Bragança, the broad Portuguese region where Miranda is located) were genotyped with the combined use of 17 Y chromosome short tandem repeats (Y-STRs) and a high resolution Y chromosome single nucleotide polymorphism (Y-SNPs) strategy. Moreover, 236 males from Miranda and neighboring regions, previously classified as R-M269, were also genotyped.

RESULTS

R-P312 was the most frequent haplogroup in the Mirandese, followed by J-12f2.1 and T-M70. The male lineages J-12f2.1 and T-M70 were also well represented, and both were shared with descendants of Sephardic Jews. No signs of diversity reduction were detected.

CONCLUSIONS

Mirandese speakers display a Y chromosome gene pool that shows a subtle differentiation from neighboring populations, mainly attributable to the assimilation of lineages ascribed to be of Jewish ancestry. Although not revealing signs of geographic/linguistic isolation, no clear affinities with other Astur-Leonese populations were detected. The results suggest that in Miranda language sharing is not accompanied by significant gene flow between populations from both sides of the political border. Am. J. Hum. Biol. 28:671-680, 2016. © 2016 Wiley Periodicals, Inc.

Origins, admixture and founder lineages in European Roma

The Roma, also known as 'Gypsies', represent the largest and the most widespread ethnic minority of Europe. There is increasing evidence, based on linguistic, anthropological and genetic data, to suggest that they originated from the Indian subcontinent, with subsequent bottlenecks and undetermined gene flow from/to hosting populations during their diaspora. Further support comes from the presence of Indian uniparentally inherited lineages, such as mitochondrial DNA M and Y-chromosome H haplogroups, in a significant number of Roma individuals. However, the limited resolution of most genetic studies so far, together with the restriction of the samples used, have prevented the detection of other non-Indian founder lineages that might have been present in the proto-Roma population. We performed a high-resolution study of the uniparental genomes of 753 Roma and 984 non-Roma hosting European individuals. Roma groups show lower genetic diversity and high heterogeneity compared with non-Roma samples as a result of lower effective population size and extensive drift, consistent with a series of bottlenecks during their diaspora. We found a set of founder lineages, present in the Roma and virtually absent in the non-Roma, for the maternal (H7, J1b3, J1c1, M18, M35b, M5a1, U3, and X2d) and paternal (I-P259, J-M92, and J-M67) genomes. This lineage classification allows us to identify extensive gene flow from non-Roma to Roma groups, whereas the opposite pattern, although not negligible, is substantially lower (up to 6.3%). Finally, the exact haplotype matching analysis of both uniparental lineages consistently points to a Northwestern origin of the proto-Roma population within the Indian subcontinent.

Common variants in BDNF, FAIM2, FTO, MC4R, NEGR1, and SH2B1 show association with obesity-related variables in Spanish Roma population

OBJECTIVES

The objective of this study is to investigate the association between previously GWAS identified genetic variants predisposing to obesity in Europeans and obesity-related phenotypes in Roma population.

METHODS

A total of 24 representative single nucleotide polymorphisms (SNPs) were genotyped in 372 individuals belonging to 50 extended families of Roma population. SNPs were tested for association with seven quantitative obesity-related phenotypes in the PLINK program.

RESULTS

Risk variants in NEGR1, FAIM2, FTO, and SH2B1 genes were associated with increased adiposity accumulation in Roma population with effect sizes between 0.21 and 0.34 Z-scores for each copy of the BMI increasing allele. Additionally, variants in BDNF and MC4R were significantly associated with adiposity distribution but not with overall fatness. No significant association was detected between obesity-related phenotypes and variants in the first intron of the FTO gene (e.g., rs9939609).

CONCLUSIONS

The results of this study suggest that SNPs in or near six genes (BDNF, FAIM2, FTO, MC4R, NEGR1, and SH2B1) are significantly associated with body fat accumulation and distribution in Roma people. However, the association observed among variants in the first intron of FTO and obesity in European derived populations is not evident in the analyzed Roma sample.

Carrier rates of four single-gene disorders in Croatian Bayash Roma

To assess how specific population history, different migration routes, isolation, and endogamy practices contributed to the distribution of several rare diseases found in specific Roma groups, we conducted a population-based research study of rare disease mutations in Croatian Vlax Roma. We tested a total of 427 subjects from Baranja and Međimurje for the presence of four mutations causing hereditary motor and sensory neuropathy type Lom (HMSNL), GM1 gangliosidosis (GM1), congenital cataracts, facial dysmorphism and neuropathy (CCFDN), and limb girdle muscle dystrophy type 2C (LGMD2C), using the RFLP-PCR method to estimate carrier frequencies. We identified a total of four individuals heterozygous for the mutation causing HMSNL in the Baranja population, with a carrier rate amounting to 1.5%. Carriers for other three mutations causing GM1, CCFDN, and LGMD2C were not found in our sample. The carrier rate for the HMSNL mutation in Baranja is lower than in other Vlax Roma groups. In addition, distinct differences in carrier rates between the Croatian Vlax groups point to different genetic history, despite their belonging to the same Roma migration category and subgroup. The difference in carrier rates is either the result of admixture or the reflection of a greater extent of genetic drift since recent founding, maintained by a high degree of endogamy.

Multiplex genotyping assays for fine-resolution subtyping of the major human Y-chromosome haplogroups E, G, I, J, and R in anthropological, genealogical, and forensic investigations

Inherited DNA polymorphisms located within the nonrecombing portion of the human Y chromosome provide a powerful means of tracking the patrilineal ancestry of male individuals. Recently, we introduced an efficient genotyping method for the detection of the basal Y-chromosome haplogroups A to T, as well as an additional method for the dissection of haplogroup O into its sublineages. To further extend the use of the Y chromosome as an evolutionary marker, we here introduce a set of genotyping assays for fine-resolution subtyping of haplogroups E, G, I, J, and R, which make up the bulk of Western Eurasian and African Y chromosomes. The marker selection includes a total of 107 carefully selected bi-allelic polymorphisms that were divided into eight hierarchically organized multiplex assays (two for haplogroup E, one for I, one for J, one for G, and three for R) based on the single-base primer extension (SNaPshot) technology. Not only does our method allow for enhanced Y-chromosome lineage discrimination, the more restricted geographic distribution of the subhaplogroups covered also enables more fine-scaled estimations of patrilineal bio-geographic origin. Supplementing our previous method for basal Y-haplogroup detection, the currently introduced assays are thus expected to be of major relevance for future DNA studies targeting male-specific ancestry for forensic, anthropological, and genealogical purposes.

Genetic evidence of an East Asian origin and paleolithic northward migration of Y-chromosome haplogroup N

The Y-chromosome haplogroup N-M231 (Hg N) is distributed widely in eastern and central Asia, Siberia, as well as in eastern and northern Europe. Previous studies suggested a counterclockwise prehistoric migration of Hg N from eastern Asia to eastern and northern Europe. However, the root of this Y chromosome lineage and its detailed dispersal pattern across eastern Asia are still unclear. We analyzed haplogroup profiles and phylogeographic patterns of 1,570 Hg N individuals from 20,826 males in 359 populations across Eurasia. We first genotyped 6,371 males from 169 populations in China and Cambodia, and generated data of 360 Hg N individuals, and then combined published data on 1,210 Hg N individuals from Japanese, Southeast Asian, Siberian, European and Central Asian populations. The results showed that the sub-haplogroups of Hg N have a distinct geographical distribution. The highest Y-STR diversity of the ancestral Hg N sub-haplogroups was observed in the southern part of mainland East Asia, and further phylogeographic analyses supports an origin of Hg N in southern China. Combined with previous data, we propose that the early northward dispersal of Hg N started from southern China about 21 thousand years ago (kya), expanding into northern China 12–18 kya, and reaching further north to Siberia about 12–14 kya before a population expansion and westward migration into Central Asia and eastern/northern Europe around 8.0–10.0 kya. This northward migration of Hg N likewise coincides with retreating ice sheets after the Last Glacial Maximum (22–18 kya) in mainland East Asia.

High prevalence of CYP2C19*2 allele in Roma samples: study on Roma and Hungarian population samples with review of the literature

The purpose of our study was to characterise the CYP2C19*2 and CYP2C19*3 alleles in healthy Roma and Hungarian populations. DNA of 500 Roma and 370 Hungarian subjects were genotyped for CYP2C19*2 (G681A, rs4244285) and CYP2C19*3 (G636A, rs4986893) by PCR-RFLP assay and direct sequencing. Significant differences were found comparing the Roma and Hungarian populations in CYP2C19 681 GG (63.6 vs. 75.9%), GA (31.8 vs. 23.0%), AA (4.6 vs. 1.1%), GA+AA (36.4 vs. 24.1%) and A allele frequencies (0.205 vs. 0.125) (p<0.004). Striking differences were found between Roma and Hungarian samples in CYP2C19*1 (79.5 vs. 87.4%) and CYP2C19*2 (20.5 vs. 12.6%) alleles, respectively (p<0.001). None of the subjects was found to carry the CYP2C19*3 allele. Frequencies of the intermedier metabolizer phenotype defined by the *1/*2 genotype (0.318 vs. 0.230, p<0.005) and poor metabolizer predicted by the *2/*2 genotype (0.046 vs. 0.011, p<0.005) was significantly higher in Roma than in Hungarians, respectively. Genotype distribution of the Roma population was similar to those of the population of North India, however, a major difference was found in the frequency of the CYP2C19*2 allele, which is likely a result of admixture with European lineages. In conclusion, the frequencies of the CYP2C19 alleles, genotypes and corresponding extensive, intermediate and poor metabolizer phenotypes studied here in the Hungarian population are similar to those of other European Caucasian populations, but display clear differences when compared to the Roma population.

Reconstructing Roma history from genome-wide data

The Roma people, living throughout Europe and West Asia, are a diverse population linked by the Romani language and culture. Previous linguistic and genetic studies have suggested that the Roma migrated into Europe from South Asia about 1,000-1,500 years ago. Genetic inferences about Roma history have mostly focused on the Y chromosome and mitochondrial DNA. To explore what additional information can be learned from genome-wide data, we analyzed data from six Roma groups that we genotyped at hundreds of thousands of single nucleotide polymorphisms (SNPs). We estimate that the Roma harbor about 80% West Eurasian ancestry-derived from a combination of European and South Asian sources-and that the date of admixture of South Asian and European ancestry was about 850 years before present. We provide evidence for Eastern Europe being a major source of European ancestry, and North-west India being a major source of the South Asian ancestry in the Roma. By computing allele sharing as a measure of linkage disequilibrium, we estimate that the migration of Roma out of the Indian subcontinent was accompanied by a severe founder event, which appears to have been followed by a major demographic expansion after the arrival in Europe.

Reconstructing the population history of European Romani from genome-wide data

The Romani, the largest European minority group with approximately 11 million people, constitute a mosaic of languages, religions, and lifestyles while sharing a distinct social heritage. Linguistic and genetic studies have located the Romani origins in the Indian subcontinent. However, a genome-wide perspective on Romani origins and population substructure, as well as a detailed reconstruction of their demographic history, has yet to be provided. Our analyses based on genome-wide data from 13 Romani groups collected across Europe suggest that the Romani diaspora constitutes a single initial founder population that originated in north/northwestern India ~1.5 thousand years ago (kya). Our results further indicate that after a rapid migration with moderate gene flow from the Near or Middle East, the European spread of the Romani people was via the Balkans starting ~0.9 kya. The strong population substructure and high levels of homozygosity we found in the European Romani are in line with genetic isolation as well as differential gene flow in time and space with non-Romani Europeans. Overall, our genome-wide study sheds new light on the origins and demographic history of European Romani.

The phylogeography of Y-chromosome haplogroup h1a1a-m82 reveals the likely Indian origin of the European Romani populations

Linguistic and genetic studies on Roma populations inhabited in Europe have unequivocally traced these populations to the Indian subcontinent. However, the exact parental population group and time of the out-of-India dispersal have remained disputed. In the absence of archaeological records and with only scanty historical documentation of the Roma, comparative linguistic studies were the first to identify their Indian origin. Recently, molecular studies on the basis of disease-causing mutations and haploid DNA markers (i.e. mtDNA and Y-chromosome) supported the linguistic view. The presence of Indian-specific Y-chromosome haplogroup H1a1a-M82 and mtDNA haplogroups M5a1, M18 and M35b among Roma has corroborated that their South Asian origins and later admixture with Near Eastern and European populations. However, previous studies have left unanswered questions about the exact parental population groups in South Asia. Here we present a detailed phylogeographical study of Y-chromosomal haplogroup H1a1a-M82 in a data set of more than 10,000 global samples to discern a more precise ancestral source of European Romani populations. The phylogeographical patterns and diversity estimates indicate an early origin of this haplogroup in the Indian subcontinent and its further expansion to other regions. Tellingly, the short tandem repeat (STR) based network of H1a1a-M82 lineages displayed the closest connection of Romani haplotypes with the traditional scheduled caste and scheduled tribe population groups of northwestern India.

Ancient migratory events in the Middle East: new clues from the Y-chromosome variation of modern Iranians

Knowledge of high resolution Y-chromosome haplogroup diversification within Iran provides important geographic context regarding the spread and compartmentalization of male lineages in the Middle East and southwestern Asia. At present, the Iranian population is characterized by an extraordinary mix of different ethnic groups speaking a variety of Indo-Iranian, Semitic and Turkic languages. Despite these features, only few studies have investigated the multiethnic components of the Iranian gene pool. In this survey 938 Iranian male DNAs belonging to 15 ethnic groups from 14 Iranian provinces were analyzed for 84 Y-chromosome biallelic markers and 10 STRs. The results show an autochthonous but non-homogeneous ancient background mainly composed by J2a sub-clades with different external contributions. The phylogeography of the main haplogroups allowed identifying post-glacial and Neolithic expansions toward western Eurasia but also recent movements towards the Iranian region from western Eurasia (R1b-L23), Central Asia (Q-M25), Asia Minor (J2a-M92) and southern Mesopotamia (J1-Page08). In spite of the presence of important geographic barriers (Zagros and Alborz mountain ranges, and the Dasht-e Kavir and Dash-e Lut deserts) which may have limited gene flow, AMOVA analysis revealed that language, in addition to geography, has played an important role in shaping the nowadays Iranian gene pool. Overall, this study provides a portrait of the Y-chromosomal variation in Iran, useful for depicting a more comprehensive history of the peoples of this area as well as for reconstructing ancient migration routes. In addition, our results evidence the important role of the Iranian plateau as source and recipient of gene flow between culturally and genetically distinct populations.

The impact of recent events on human genetic diversity

The historical record tells us stories of migrations, population expansions and colonization events in the last few thousand years, but what was their demographic impact? Genetics can throw light on this issue, and has mostly done so through the maternally inherited mitochondrial DNA (mtDNA) and the male-specific Y chromosome. However, there are a number of problems, including marker ascertainment bias, possible influences of natural selection, and the obscuring layers of the palimpsest of historical and prehistorical events. Y-chromosomal lineages are particularly affected by genetic drift, which can be accentuated by recent social selection. A diversity of approaches to expansions in Europe is yielding insights into the histories of Phoenicians, Roma, Anglo-Saxons and Vikings, and new methods for producing and analysing genome-wide data hold much promise. The field would benefit from more consensus on appropriate methods, and better communication between geneticists and experts in other disciplines, such as history, archaeology and linguistics.

Ancestral modal Y-STR haplotype shared among Romani and South Indian populations

One of the primary unanswered questions regarding the dispersal of Romani populations concerns the geographical region and/or the Indian caste/tribe that gave rise to the proto-Romani group. To shed light on this matter, 161 Y-chromosomes from Roma, residing in two different provinces of Serbia, were analyzed. Our results indicate that the paternal gene pool of both groups is shaped by several strata, the most prominent of which, H1-M52, comprises almost half of each collection's patrilineages. The high frequency of M52 chromosomes in the two Roma populations examined may suggest that they descend from a single founder that has its origins in the Indian subcontinent. Moreover, when the Y-STR profiles of haplogroup H derived individuals in our Roma populations were compared to those typed in the South Indian emigrants from Malaysia and groups from Madras, Karnataka (Lingayat and Vokkaliga castes) and tribal Soligas, sharing of the two most common haplotypes was observed. These similarities suggest that South India may have been one of the contributors to the proto-Romanis. European genetic signatures (i.e., haplogroups E1b1b1a1b-V13, G2a-P15, I-M258, J2-M172 and R1-M173), on the other hand, were also detected in both groups, but at varying frequencies. The divergent European genetic signals in each collection are likely the result of differential gene flow and/or admixture with the European host populations but may also be attributed to dissimilar endogamous practices following the initial founder effect. Our data also support the notion that a number of haplogroups including G2a-P15, J2a3b-M67(xM92), I-M258 and E1b1b1-M35 were incorporated into the proto-Romani paternal lineages as migrants moved from northern India through Southwestern Asia, the Middle East and/or Anatolia into the Balkans.

Refining the genetic portrait of Portuguese Roma through X-chromosomal markers

Due to differences in transmission between X-chromosomal and autosomal DNA, the comparison of data derived from both markers allows deeper insight into the forces that shape the patterns of genetic diversity in populations. In this study, we applied this comparative approach to a sample of Portuguese Roma (Gypsies) by analyzing 43 X-chromosomal markers and 53 autosomal markers. Portuguese individuals of non-Gypsy ancestry were also studied. Compared with the host population, reduced levels of diversity on the X chromosome and autosomes were detected in Gypsies; this result was in line with known patterns of genetic diversity typical of Roma groups. As a consequence of the complex demographic past of the Roma, during which admixture and genetic drift played major roles, the amount of linkage disequilibrium (LD) on the X chromosome in Gypsies was considerably higher than that observed in non-Gypsies. When the pattern of differentiation on the X chromosome was compared with that of autosomes, there was evidence for asymmetries in female and male effective population sizes during the admixture between Roma and non-Roma. This result supplements previous data provided by mtDNA and the Y chromosome, underlining the importance of using combined information from the X chromosome and autosomes to dissect patterns of genetic diversity. Following the out-of-India dispersion, the Roma acquired a complex genetic pattern that was influenced by drift and introgression with surrounding populations, with important contributions from both males and females. We provide evidence that a sex-biased admixture with Europeans is probably associated with the founding of the Portuguese Gypsies.

A world in a grain of sand: human history from genetic data

Genome-wide genotypes and sequences are enriching our understanding of the past 50,000 years of human history and providing insights into earlier periods largely inaccessible to mitochondrial DNA and Y-chromosomal studies.

To see a world in a grain of sand ...

William Blake, Auguries of Innocence

Reconstructing the Indian origin and dispersal of the European Roma: a maternal genetic perspective

Previous genetic, anthropological and linguistic studies have shown that Roma (Gypsies) constitute a founder population dispersed throughout Europe whose origins might be traced to the Indian subcontinent. Linguistic and anthropological evidence point to Indo-Aryan ethnic groups from North-western India as the ancestral parental population of Roma. Recently, a strong genetic hint supporting this theory came from a study of a private mutation causing primary congenital glaucoma. In the present study, complete mitochondrial control sequences of Iberian Roma and previously published maternal lineages of other European Roma were analyzed in order to establish the genetic affinities among Roma groups, determine the degree of admixture with neighbouring populations, infer the migration routes followed since the first arrival to Europe, and survey the origin of Roma within the Indian subcontinent. Our results show that the maternal lineage composition in the Roma groups follows a pattern of different migration routes, with several founder effects, and low effective population sizes along their dispersal. Our data allowed the confirmation of a North/West migration route shared by Polish, Lithuanian and Iberian Roma. Additionally, eleven Roma founder lineages were identified and degrees of admixture with host populations were estimated. Finally, the comparison with an extensive database of Indian sequences allowed us to identify the Punjab state, in North-western India, as the putative ancestral homeland of the European Roma, in agreement with previous linguistic and anthropological studies.

Genetic structure of the paternal lineage of the Roma people

According to written sources, Roma (Romanies, Gypsies) arrived in the Balkans around 1,000 years ago from India and have subsequently spread through several parts of Europe. Genetic data, particularly from the Y chromosome, have supported this model, and can potentially refine it. We now provide an analysis of Y-chromosomal markers from five Roma and two non-Roma populations (N = 787) in order to investigate the genetic relatedness of the Roma population groups to one another, and to gain further understanding of their likely Indian origins, the genetic contribution of non-Roma males to the Roma populations, and the early history of their splits and migrations in Europe. The two main sources of the Roma paternal gene pool were identified as South Asian and European. The reduced diversity and expansion of H1a-M82 lineages in all Roma groups imply shared descent from a single paternal ancestor in the Indian subcontinent. The Roma paternal gene pool also contains a specific subset of E1b1b1a-M78 and J2a2-M67 lineages, implying admixture during early settlement in the Balkans and the subsequent influx into the Carpathian Basin. Additional admixture, evident in the low and moderate frequencies of typical European haplogroups I1-M253, I2a-P37.2, I2b-M223, R1b1-P25, and R1a1-M198, has occurred in a more population-specific manner.

Divergent patrilineal signals in three Roma populations

Previous studies have revealed that the European Roma share close genetic, linguistic and cultural similarities with Indian populations despite their disparate geographical locations and divergent demographic histories. In this study, we report for the first time Y-chromosome distributions in three Roma collections residing in Belgrade, Vojvodina and Kosovo. Eighty-eight Y-chromosomes were typed for 14 SNPs and 17 STRs. The data were subsequently utilized for phylogenetic comparisons to pertinent reference collections available from the literature. Our results illustrate that the most notable difference among the three Roma populations is in their opposing distributions of haplogroups H and E. Although the Kosovo and Belgrade samples exhibit elevated levels of the Indian-specific haplogroup H-M69, the Vojvodina collection is characterized almost exclusively by haplogroup E-M35 derivatives, most likely the result of subsequent admixture events with surrounding European populations. Overall, the available data from Romani groups points to different levels of gene flow from local populations.

Paternal genetic history of the Vlax Roma

Romanies constitute the largest minority group belonging to different subgroups in Hungary. Vlax Romanies are one of these Romani subgroups. The Gypsies came to Hungary from the Balkans in two large migrations. The Carpathian Romanies arrived in the 15th century and the Vlax Romanies came in the 19th century. The Carpathian Gypsies speak Hungarian and the Vlax Romanies speak Hungarian and Romani languages. Only a limited number of genetic studies of Y-chromosomal haplotypes/haplogroups have been done before, moreover most studies did not contain information regarding the investigated Roma populations which subgroups belong to. In the present study, we analyzed a wide set of Y-chromosomal markers to do comparable studies of the Vlax Roma in eastern Hungarian regions. The results can be compared in the context of previously published data on other Romani groups, Indian and Hungarian reference populations. Haplogroups H1a-M82 and J2a2-M67 were most common in the investigated population groups. A median-joining network of haplogroup H1a-M82 has demonstrated the sharing of identical Indian specific Y-chromosomal lineages between all Romani populations including Malaysian Indians as well as the Vlax Romanies. This common lineage of haplogroup H1a-M82 represents a common descent from a single ancestor provides a strong genetic link to the ancestral geographical origin of the proto-Gypsies. The detected haplogroups in the Vlax Romani population groups can be classified into two different Y-chromosomal lineages based on their putative origin. These lineages include ancestral Indian (H1a-M82), present-day Eurasian (J2a2-M67, J2*-M172, E1b1b1a-M78, I1-M253, R1a1-M198 and R1b1-P25) Y-chromosome lineages. Presence of these lineages in the paternal gene pool of the Roma people is illustrative of the Gypsy migration route from India through the Balkan to the Carpathian Basin.

A genetic historical sketch of European Gypsies: The perspective from autosomal markers

In this study, 123 unrelated Portuguese Gypsies were analyzed for 15 highly polymorphic autosomal short tandem repeats (STRs). Average gene diversity across the 15 markers was 76.7%, which is lower than that observed in the non-Gypsy Portuguese population. Subsets of STRs were used to perform comparisons with other Gypsy and corresponding host populations. Interestingly, diversity reduction in Gypsy groups compared to their non-Gypsy surrounding populations apparently varied according to an East-West gradient, which parallels their dispersion in Europe as well as a decrease in complexity of their internal structure. Analysis of genetic distances revealed that the average level of genetic differentiation between Gypsy groups was much larger than that observed between the corresponding non-Gypsy populations. The high rate of heterogeneity among Gypsies can be explained by strong genetic drift and limited intergroup gene flow. However, when genetic relationships were addressed through principal component analysis, all Gypsy populations clustered together and was clearly distinguished from other populations, a pattern that suggests their common origin. Concerning the putative ancestral genetic component, admixture analysis did not reveal strong Indian ancestry in the current Gypsy gene pools, in contrast to the high admixture estimates for either Europeans or Western Asians.

Extended Y chromosome investigation suggests postglacial migrations of modern humans into East Asia via the northern route

Genetic diversity data, from Y chromosome and mitochondrial DNA as well as recent genome-wide autosomal single nucleotide polymorphisms, suggested that mainland Southeast Asia was the major geographic source of East Asian populations. However, these studies also detected Central-South Asia (CSA)- and/or West Eurasia (WE)-related genetic components in East Asia, implying either recent population admixture or ancient migrations via the proposed northern route. To trace the time period and geographic source of these CSA- and WE-related genetic components, we sampled 3,826 males (116 populations from China and 1 population from North Korea) and performed high-resolution genotyping according to the well-resolved Y chromosome phylogeny. Our data, in combination with the published East Asian Y-haplogroup data, show that there are four dominant haplogroups (accounting for 92.87% of the East Asian Y chromosomes), O-M175, D-M174, C-M130 (not including C5-M356), and N-M231, in both southern and northern East Asian populations, which is consistent with the proposed southern route of modern human origin in East Asia. However, there are other haplogroups (6.79% in total) (E-SRY4064, C5-M356, G-M201, H-M69, I-M170, J-P209, L-M20, Q-M242, R-M207, and T-M70) detected primarily in northern East Asian populations and were identified as Central-South Asian and/or West Eurasian origin based on the phylogeographic analysis. In particular, evidence of geographic distribution and Y chromosome short tandem repeat (Y-STR) diversity indicates that haplogroup Q-M242 (the ancestral haplogroup of the native American-specific haplogroup Q1a3a-M3) and R-M207 probably migrated into East Asia via the northern route. The age estimation of Y-STR variation within haplogroups suggests the existence of postglacial (∼18 Ka) migrations via the northern route as well as recent (∼3 Ka) population admixture. We propose that although the Paleolithic migrations via the southern route played a major role in modern human settlement in East Asia, there are ancient contributions, though limited, from WE, which partly explain the genetic divergence between current southern and northern East Asian populations.

Y-STR variation in Albanian populations: implications on the match probabilities and the genetic legacy of the minority claiming an Egyptian descent

Y chromosome variation at 12 STR (the Powerplex® Y system core set) and 18 binary markers was investigated in two major (the Ghegs and the Tosks) and two minor (the Gabels and the Jevgs) populations from Albania (Southern Balkans). The large proportion of haplotypes shared within and between groups makes the Powerplex 12-locus set inadequate to ensure a suitable power of discrimination for the forensic practice. At least 85% of Y lineages in the Jevgs, the cultural minority claiming an Egyptian descent, turned out to be of either Roma or Balkan ancestry. They also showed unequivocal signs of a common genetic history with the Gabels, the other Albanian minority practising social and cultural Roma traditions.

Dissecting the molecular architecture and origin of Bayash Romani patrilineages: genetic influences from South-Asia and the Balkans

The Bayash are a branch of Romanian speaking Roma living dispersedly in Central, Eastern, and Southeastern Europe. To better understand the molecular architecture and origin of the Croatian Bayash paternal gene pool, 151 Bayash Y chromosomes were analyzed for 16 SNPs and 17 STRs and compared with European Romani and non-Romani majority populations from Europe, Turkey, and South Asia. Two main layers of Bayash paternal gene pool were identified: ancestral (Indian) and recent (European). The reduced diversity and expansion signals of H1a patrilineages imply descent from closely related paternal ancestors who could have settled in the Indian subcontinent, possibly as early as between the eighth and tenth centuries AD. The recent layer of the Bayash paternal pool is dominated by a specific subset of E1b1b1a lineages that are not found in the Balkan majority populations. At least two private mutational events occurred in the Bayash during their migrations from the southern Balkans toward Romania. Additional admixture, evident in the low frequencies of typical European haplogroups, J2, R1a, I1, R1b1b2, G, and I2a, took place primarily during the early Bayash settlement in the Balkans and the Romani bondage in Romania. Our results indicate two phenomena in the Bayash and analyzed Roma: a significant preservation of ancestral H1a haplotypes as a result of considerable, but variable level of endogamy and isolation and differential distribution of less frequent, but typical European lineages due to different patterns of the early demographic history in Europe marked by differential admixture and genetic drift.