Béla Melegh

Bio: Béla Melegh is an academic researcher from University of Pécs. The author has contributed to research in topics: Population & Haplotype. The author has an hindex of 15, co-authored 30 publications receiving 824 citations.

Parallel palaeogenomic transects reveal complex genetic history of early European farmers.

Abstract: In European Neolithic populations, the arrival of farmers prompted admixture with local hunter-gatherers over many centuries, resulting in distinct signatures in each region due to a complex series of interactions. David Reich and colleagues analyse genome-wide data from 180 individuals from the Neolithic and Chalcolithic periods of Hungary, Germany and Spain to study the population dynamics of Neolithization in European prehistory. They examine how gene flow reshaped European populations during the Neolithic period, including pervasive admixture—the interbreeding between previously isolated populations—between groups with different ancestry profiles. In each region, they find that the arrival of farmers prompted admixture with local hunter-gatherers, over the course of 3,000 years. Ancient DNA studies have established that Neolithic European populations were descended from Anatolian migrants1,2,3,4,5,6,7,8 who received a limited amount of admixture from resident hunter-gatherers3,4,5,9. Many open questions remain, however, about the spatial and temporal dynamics of population interactions and admixture during the Neolithic period. Here we investigate the population dynamics of Neolithization across Europe using a high-resolution genome-wide ancient DNA dataset with a total of 180 samples, of which 130 are newly reported here, from the Neolithic and Chalcolithic periods of Hungary (6000–2900 bc, n = 100), Germany (5500–3000 bc, n = 42) and Spain (5500–2200 bc, n = 38). We find that genetic diversity was shaped predominantly by local processes, with varied sources and proportions of hunter-gatherer ancestry among the three regions and through time. Admixture between groups with different ancestry profiles was pervasive and resulted in observable population transformation across almost all cultural transitions. Our results shed new light on the ways in which gene flow reshaped European populations throughout the Neolithic period and demonstrate the potential of time-series-based sampling and modelling approaches to elucidate multiple dimensions of historical population interactions.

Genetic diversity and zoonotic potential of human rotavirus strains, 2003–2006, hungary

Abstract: Rotavirus strain surveillance is being conducted in many countries before and after introduction of newly licensed vaccines to assess the impact of the vaccines on rotavirus strains. Here we describe a strain surveillance study in the Budapest area of Hungary (2003–2006) based on RNA profile analysis, genotyping by multiplex PCR and nucleotide sequencing. Among 1,983 G-typed rotaviruses we identified G1 (22%), G2 (4.8%), G3 (3.5%), G4 (18.5%), G6 (1.1%), G8 (<0.1%, n = 1), G9 (42%), and G12 (3.4%) specificities. Information on P genotype incidence was determined for a subset of samples (n = 814). In addition to the globally important strains, a variety of uncommon antigen combinations were also found, for example, P[9],G3; P[14],G6; or P[14],G8. Sequence and phylogenetic analysis of the VP7, VP4, VP6, and NSP4 genes of selected strains with uncommon antigen combinations demonstrated high similarity with certain bovine, porcine, feline, equine, and lapine rotaviruses, respectively. Continued surveillance is needed to assess the role of animal rotaviruses in human diseases. J. Med. Virol. 81:362–370, 2009. © 2008 Wiley-Liss, Inc.

Reconstructing Roma History from Genome-Wide Data

Abstract: 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.

Apolipoprotein A5 T-1131C variant confers risk for metabolic syndrome.

Abstract: The −1131C is a naturally occurring variant of the apolipoprotein A5 (ApoA5) gene, which has been shown to associate with increased triglyceride levels. This variant has also been shown to confer risk for development of ischemic heart disease and stroke. The gene is in linkage disequilibrium with factors known to correlate with impaired glucose homeostasis. These observations prompted us to study the prevalence of the ApoA5 –1131C allele in patients with metabolic syndrome. A total of 201 metabolic syndrome patients and 210 controls were studied. In both groups the triglyceride levels of patients with −1131C allele were significantly increased compared to the subjects with −1131T allele (3.22 ±0.43 mmol/1 vs. 2.24 ±0.12 mmol/1, p<0.01 in the metabolic syndrome patients; 2.10 ±0.19 mmol/1 vs. 1.22 ±0.05 mmol/1, p<0.01 in the controls). In metabolic syndrome patients the prevalence of the ApoA5 –1131C variant was increased compared to the healthy controls (11% vs. 6.20%). Multiplex regression analysis model adjusted for age, gender, serum total cholesterol levels, acute myocardial infarction and stroke events revealed that the examined ApoA5 variant confers risk for the development of metabolic syndrome: the odds ratio at 95% confidence interval was 3.622 (1.200–10.936), p=0.02. Our findings strongly suggest that this variant is a risk factor for the development of hypertriglyceridemia and metabolic syndrome.

Emergence of serotype G12 rotaviruses, Hungary.

Abstract: We describe the emergence of serotype G12 rotaviruses (67 [6.9%] of 971 specimens tested) among children hospitalized with rotavirus gastroenteritis in Hungary during 2005. These findings are consistent with recent reports of the possible global spread and increasing epidemiologic importance of these strains, which may have implications for current rotavirus vaccination strategies.

The Beaker phenomenon and the genomic transformation of northwest Europe

Abstract: From around 2750 to 2500 bc, Bell Beaker pottery became widespread across western and central Europe, before it disappeared between 2200 and 1800 bc. The forces that propelled its expansion are a matter of long-standing debate, and there is support for both cultural diffusion and migration having a role in this process. Here we present genome-wide data from 400 Neolithic, Copper Age and Bronze Age Europeans, including 226 individuals associated with Beaker-complex artefacts. We detected limited genetic affinity between Beaker-complex-associated individuals from Iberia and central Europe, and thus exclude migration as an important mechanism of spread between these two regions. However, migration had a key role in the further dissemination of the Beaker complex. We document this phenomenon most clearly in Britain, where the spread of the Beaker complex introduced high levels of steppe-related ancestry and was associated with the replacement of approximately 90% of Britain's gene pool within a few hundred years, continuing the east-to-west expansion that had brought steppe-related ancestry into central and northern Europe over the previous centuries.

The genomic history of southeastern Europe

Abstract: Farming was first introduced to Europe in the mid-seventh millennium bc, and was associated with migrants from Anatolia who settled in the southeast before spreading throughout Europe. Here, to und ...

Ancient human genomes suggest three ancestral populations for present-day Europeans

Abstract: We sequenced the genomes of a ∼7,000-year-old farmer from Germany and eight ∼8,000-year-old hunter-gatherers from Luxembourg and Sweden. We analysed these and other ancient genomes with 2,345 contemporary humans to show that most present-day Europeans derive from at least three highly differentiated populations: west European hunter-gatherers, who contributed ancestry to all Europeans but not to Near Easterners; ancient north Eurasians related to Upper Palaeolithic Siberians, who contributed to both Europeans and Near Easterners; and early European farmers, who were mainly of Near Eastern origin but also harboured west European hunter-gatherer related ancestry. We model these populations' deep relationships and show that early European farmers had ∼44% ancestry from a 'basal Eurasian' population that split before the diversification of other non-African lineages.

Inferring Admixture Histories of Human Populations Using Linkage Disequilibrium

Abstract: Long-range migrations and the resulting admixtures between populations have been important forces shaping human genetic diversity. Most existing methods for detecting and reconstructing historical admixture events are based on allele frequency divergences or patterns of ancestry segments in chromosomes of admixed individuals. An emerging new approach harnesses the exponential decay of admixture-induced linkage disequilibrium (LD) as a function of genetic distance. Here, we comprehensively develop LD-based inference into a versatile tool for investigating admixture. We present a new weighted LD statistic that can be used to infer mixture proportions as well as dates with fewer constraints on reference populations than previous methods. We define an LD-based three-population test for admixture and identify scenarios in which it can detect admixture events that previous formal tests cannot. We further show that we can uncover phylogenetic relationships among populations by comparing weighted LD curves obtained using a suite of references. Finally, we describe several improvements to the computation and fitting of weighted LD curves that greatly increase the robustness and speed of the calculations. We implement all of these advances in a software package, ALDER, which we validate in simulations and apply to test for admixture among all populations from the Human Genome Diversity Project (HGDP), highlighting insights into the admixture history of Central African Pygmies, Sardinians, and Japanese.