Y-Chromosome Diversity in Modern Bulgarians: New Clues about Their Ancestry

To better define the structure and origin of the Bulgarian paternal gene pool, we have examined the Y-chromosome variation in 808 Bulgarian males. The analysis was performed by high-resolution genotyping of biallelic markers and by analyzing the STR variation within the most informative haplogroups. We found that the Y-chromosome gene pool in modern Bulgarians is primarily represented by Western Eurasian haplogroups with , 40% belonging to haplogroups E-V13 and I-M423, and 20% to R-M17. Haplogroups common in the Middle East (J and G) and in South Western Asia (R-L23*) occur at frequencies of 19% and 5%, respectively. Haplogroups C, N and Q, distinctive for Altaic and Central Asian Turkic-speaking populations, occur at the negligible frequency of only 1.5%. Principal Component analyses group Bulgarians with European populations, apart from Central Asian Turkic-speaking groups and South Western Asia populations. Within the country, the genetic variation is structured in Western, Central and Eastern Bulgaria indicating that the Balkan Mountains have been permeable to human movements. The lineage analysis provided the following interesting results: (i) R-L23* is present in Eastern Bulgaria since the post glacial period; (ii) haplogroup E-V13 has a Mesolithic age in Bulgaria from where it expanded after the arrival of farming; (iii) haplogroup J-M241 probably reflects the Neolithic westward expansion of farmers from the earliest sites along the Black Sea. On the whole, in light of the most recent historical studies, which indicate a substantial proto-Bulgarian input to the contemporary Bulgarian people, our data suggest that a common paternal ancestry between the proto-Bulgarians and the Altaic and Central Asian Turkic-speaking populations either did not exist or was negligible

Consequences of the 118A>G polymorphism in the OPRMI gene: Translation from bench to bedside?

The 118A>G single nucleotide polymorphism (SNP) in the μ-opioid receptor (OPRM1) gene has been the most described variant in pharmacogenetic studies regarding opioid drugs. Despite evidence for an altered biological function encoded by this variant, this knowledge is not yet utilized clinically. The aim of the present review was to collect and discuss the available information on the 118A>G SNP in the OPRM1 gene, at the molecular level and in its clinical manifestations. In vitro biochemical and molecular assays have shown that the variant receptor has higher binding affinity for β-endorphins, that it has altered signal transduction cascade, and that it has a lower expression compared with wild-type OPRM1. Studies using animal models for 118A>G have revealed a double effect of the variant receptor, with an apparent gain of function with respect to the response to endogenous opioids but a loss of function with exogenous administered opioid drugs. Although patients with this variant have shown a lower pain threshold and a higher drug consumption in order to achieve the analgesic effect, clinical experiences have demonstrated that patients carrying the variant allele are not affected by the increased opioid consumption in terms of side effects

The initial peopling of the Americas: a growing number of founding mitochondrial genomes from Beringia

Pan-American mitochondrial DNA (mtDNA) haplogroup C1 has been recently subdivided into three branches, two of which (C1b and C1c) are characterized by ages and geographical distributions that are indicative of an early arrival from Beringia with Paleo-Indians. In contrast, the estimated ages of C1d—the third subset of C1—looked too young to fit the above scenario. To define the origin of this enigmatic C1 branch, we completely sequenced 63 C1d mitochondrial genomes from a wide range of geographically diverse, mixed, and indigenous American populations. The revised phylogeny not only brings the age of C1d within the range of that of its two sister clades, but reveals that there were two C1d founder genomes for Paleo-Indians. Thus, the recognized maternal founding lineages of Native Americans are at least 15, indicating that the overall number of Beringian or Asian founder mitochondrial genomes will probably increase extensively when all Native American haplogroups reach the same level of phylogenetic and genomic resolution as obtained here for C1d.Fil: Perego, Ugo A.. Soreson Molecular Genealogy Foundation; Estados Unidos. Università di Pavia. Dipartimento di Genetica e Microbiologia; ItaliaFil: Angerhofer, Norman. Soreson Molecular Genealogy Foundation; Estados UnidosFil: Pala, Maria. Università di Pavia. Dipartimento di Genetica e Microbiologia; ItaliaFil: Olivieri, Anna. Università di Pavia. Dipartimento di Genetica e Microbiologia; ItaliaFil: Lancioni, Hovirag. Universita Di Perugia; ItaliaFil: Kashani, Baharak Hooshiar. Università di Pavia. Dipartimento di Genetica e Microbiologia; ItaliaFil: Carossa, Valeria. Università di Pavia. Dipartimento di Genetica e Microbiologia; ItaliaFil: Ekins, Jayne E.. Soreson Molecular Genealogy Foundation; Estados UnidosFil: Gómez Carballa, Alberto. Universidad de Santiago de Compostela; EspañaFil: Huber, Gabriela. Universidad de Innsbruck; AustriaFil: Zimmermann, Bettina. Universidad de Innsbruck; AustriaFil: Corach, Daniel. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Servicio de Huellas Digitales Genéticas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Babudri, Nora. Universita Di Perugia; ItaliaFil: Panara, Fausto. Universita Di Perugia; ItaliaFil: Myres, Natalie M.. Soreson Molecular Genealogy Foundation; Estados UnidosFil: Parson, Walther. Universidad de Innsbruck; AustriaFil: Semino, Ornella. Università di Pavia. Dipartimento di Genetica e Microbiologia; ItaliaFil: Salas, Antonio. Universidad de Santiago de Compostela; EspañaFil: Woodward, Scott R.. Soreson Molecular Genealogy Foundation; Estados UnidosFil: Achilli, Alessandro. Università di Pavia. Dipartimento di Genetica e Microbiologia; Italia. Universita Di Perugia; ItaliaFil: Torroni, Antonio. Università di Pavia. Dipartimento di Genetica e Microbiologia; Itali

Mitochondrial DNA signals of late glacial recolonization of Europe from near Eastern refugia

Human populations, along with those of many other species, are thought to have contracted into a number of refuge areas at the height of the last Ice Age. European populations are believed to be, to a large extent, the descendants of the inhabitants of these refugia, and some extant mtDNA lineages can be traced to refugia in Franco-Cantabria (haplogroups H1, H3, V, and U5b1), the Italian Peninsula (U5b3), and the East European Plain (U4 and U5a). Parts of the Near East, such as the Levant, were also continuously inhabited throughout the Last Glacial Maximum, but unlike western and eastern Europe, no archaeological or genetic evidence for Late Glacial expansions into Europe from the Near East has hitherto been discovered. Here we report, on the basis of an enlarged whole-genome mitochondrial database, that a substantial, perhaps predominant, signal from mitochondrial haplogroups J and T, previously thought to have spread primarily from the Near East into Europe with the Neolithic population, may in fact reflect dispersals during the Late Glacial period, ?19–12 thousand years (ka) ago.<br/

Mitochondrial DNA Backgrounds Might Modulate Diabetes Complications Rather than T2DM as a Whole

Mitochondrial dysfunction has been implicated in rare and common forms of type 2 diabetes (T2DM). Additionally, rare mitochondrial DNA (mtDNA) mutations have been shown to be causal for T2DM pathogenesis. So far, many studies have investigated the possibility that mtDNA variation might affect the risk of T2DM, however, when found, haplogroup association has been rarely replicated, even in related populations, possibly due to an inadequate level of haplogroup resolution. Effects of mtDNA variation on diabetes complications have also been proposed. However, additional studies evaluating the mitochondrial role on both T2DM and related complications are badly needed. To test the hypothesis of a mitochondrial genome effect on diabetes and its complications, we genotyped the mtDNAs of 466 T2DM patients and 438 controls from a regional population of central Italy (Marche). Based on the most updated mtDNA phylogeny, all 904 samples were classified into 57 different mitochondrial sub-haplogroups, thus reaching an unprecedented level of resolution. We then evaluated whether the susceptibility of developing T2DM or its complications differed among the identified haplogroups, considering also the potential effects of phenotypical and clinical variables. MtDNA backgrounds, even when based on a refined haplogroup classification, do not appear to play a role in developing T2DM despite a possible protective effect for the common European haplogroup H1, which harbors the G3010A transition in the MTRNR2 gene. In contrast, our data indicate that different mitochondrial haplogroups are significantly associated with an increased risk of specific diabetes complications: H (the most frequent European haplogroup) with retinopathy, H3 with neuropathy, U3 with nephropathy, and V with renal failure

Genetic variation in Bulgarians: a mitochondrial DNA perspective

The structure and diversity of the Bulgarian mitochondrial DNA (mtDNA) gene pool is still almost unknown. In the present study, we have evaluated the extent and nature of mtDNA variation in a very large sample of Bulgarians, comprising 855 healthy unrelated subjects from across the country. The analysis was performed by sequencing about 850 base pairs (from np 16000 to np 250) of the mtDNA control region, followed by the hierarchical RFLP survey of numerous diagnostic coding-region markers. Overall, this approach allowed the identification of 586 different haplotypes and their classification into 79 known haplogroups or paragroups. The observed pattern of mtDNA diversity in Bulgarians is mainly shaped by haplogroups (H and U) dated to the Upper Paleolithic period. The spread of majority of the subclades of these haplogroups is related with waves of post-LGM recolonization. A fraction of the Bulgarian mtDNA gene pool is allocated to haplogroups, which represent Neolithic genetic component. In the comparisons of the observed haplogroup frequencies with those from a wide range of western Eurasian populations, Bulgarians do not group with the great majority of other Europeans and differ substantially from Near Eastern populations. This reflects the peculiarity of the Bulgarian mtDNA gene pool, determined by its history and demographic processes

Bulgarians vs the other European populations: a mitochondrial DNA perspective

To define the matrilineal relationships between Bulgarians and other European populations, we have evaluated the mitochondrial DNA (mtDNA) variation in a sample of 855 Bulgarian subjects from the mtDNA perspective. The molecular survey was performed by sequencing ∼750 bp of the control region, which resulted in 557 different haplotypes, and by a subsequent restriction fragment length polymorphism analysis to confirm haplogroup/subhaplogroup affiliation. The classification was carried out according to the most updated criteria as reported by van Oven and Kayser (Hum Mutat 30:386–394, 2009), allowing the identification of 45 mitochondrial clades. The observed pattern of mtDNA variation indicates that the Bulgarian mitochondrial pool is geographically homogeneous across the country, and that is characterized by an overall extremely high frequency of western Eurasian lineages. In the principal component analysis, Bulgarians locate in an intermediate position between Eastern European and Mediterranean populations, which is in agreement with historical events. Thus, while the Mediterranean legacy could be attributed to the Thracians, indigenous people that firstly inhabited the Balkans, the Eastern contribution is likely due to the Proto-Bulgarians originating from the Middle East and to the Slavs migrating from northeast Europe

Y-Chromosome Diversity in Modern Bulgarians: New Clues about Their Ancestry

<div><p>To better define the structure and origin of the Bulgarian paternal gene pool, we have examined the Y-chromosome variation in 808 Bulgarian males. The analysis was performed by high-resolution genotyping of biallelic markers and by analyzing the STR variation within the most informative haplogroups. We found that the Y-chromosome gene pool in modern Bulgarians is primarily represented by Western Eurasian haplogroups with ∼ 40% belonging to haplogroups E-V13 and I-M423, and 20% to R-M17. Haplogroups common in the Middle East (J and G) and in South Western Asia (R-L23*) occur at frequencies of 19% and 5%, respectively. Haplogroups C, N and Q, distinctive for Altaic and Central Asian Turkic-speaking populations, occur at the negligible frequency of only 1.5%. Principal Component analyses group Bulgarians with European populations, apart from Central Asian Turkic-speaking groups and South Western Asia populations. Within the country, the genetic variation is structured in Western, Central and Eastern Bulgaria indicating that the Balkan Mountains have been permeable to human movements. The lineage analysis provided the following interesting results: (i) R-L23* is present in Eastern Bulgaria since the post glacial period; (ii) haplogroup E-V13 has a Mesolithic age in Bulgaria from where it expanded after the arrival of farming; (iii) haplogroup J-M241 probably reflects the Neolithic westward expansion of farmers from the earliest sites along the Black Sea. On the whole, in light of the most recent historical studies, which indicate a substantial proto-Bulgarian input to the contemporary Bulgarian people, our data suggest that a common paternal ancestry between the proto-Bulgarians and the Altaic and Central Asian Turkic-speaking populations either did not exist or was negligible.</p> </div

Analysis of molecular variance in populations of the former nine provinces of Bulgaria.

*<p>p≈0.05.</p

Principal components plots based on Y-chromosome haplogroup frequencies.

<p>(A) African and Eurasian populations analyzed at the highest level of phylogenetic resolution, (B) Bulgaria in the European context, at a lower level of phylogenetic resolution, and (C) Bulgaria in the Asian context, based only on informative Asian markers. Data and abbreviations are provided in Tables 2–4. Numbers in brackets indicate the proportion of the total genetic information retained by a given PC. Inset plot illustrates the contribution of each haplogroup.</p