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Journal Article Archive 2016-10-14T01:03:42+00:00

Journal Article Archive

The Genomic History Of Southeastern Europe

Journal: bioRxiv | Year: 2017


Farming was first introduced to southeastern Europe in the mid-7th millennium BCE – brought by migrants from Anatolia who settled in the region before spreading throughout Europe. However, the dynamics of the interaction between the first farmers and the indigenous hunter-gatherers remain poorly understood because of the near absence of ancient DNA from the region. We report new genome-wide ancient DNA data from 204 individuals-65 Paleolithic and Mesolithic, 93 Neolithic, and 46 Copper, Bronze and Iron Age-who lived in southeastern Europe and surrounding regions between about 12,000 and 500 BCE. We document that the hunter-gatherer populations of southeastern Europe, the Baltic, and the North Pontic Steppe were distinctive from those of western Europe, with a West-East cline of ancestry. We show that the people who brought farming to Europe were not part of a single population, as early farmers from southern Greece are not descended from the Neolithic population of northwestern Anatolia that was ancestral to all other European farmers. The ancestors of the first farmers of northern and western Europe passed through southeastern Europe with limited admixture with local hunter-gatherers, but we show that some groups that remained in the region mixed extensively with local hunter-gatherers, with relatively sex-balanced admixture compared to the male-biased hunter-gatherer admixture that we show prevailed later in the North and West. After the spread of farming, southeastern Europe continued to be a nexus between East and West, with intermittent steppe ancestry, including in individuals from the Varna I cemetery and associated with the Cucuteni-Trypillian archaeological complex, up to 2,000 years before the Steppe migration that replaced much of northern Europe's population.

Peoples: | Places: | Topics: | DNA Type: Ancient DNA, Autosomal DNA, mtDNA, X-DNA, and Y-DNA

The Geography of Recent Genetic Ancestry across Europe

Journal: PLoS Biology | Year: 2013


The recent genealogical history of human populations is a complex mosaic formed by individual migration, large-scale population movements, and other demographic events. Population genomics datasets can provide a window into this recent history, as rare traces of recent shared genetic ancestry are detectable due to long segments of shared genomic material. We make use of genomic data for 2,257 Europeans (in the Population Reference Sample [POPRES] dataset) to conduct one of the first surveys of recent genealogical ancestry over the past 3,000 years at a continental scale. We detected 1.9 million shared long genomic segments, and used the lengths of these to infer the distribution of shared ancestors across time and geography. We find that a pair of modern Europeans living in neighboring populations share around 2–12 genetic common ancestors from the last 1,500 years, and upwards of 100 genetic ancestors from the previous 1,000 years. These numbers drop off exponentially with geographic distance, but since these genetic ancestors are a tiny fraction of common genealogical ancestors, individuals from opposite ends of Europe are still expected to share millions of common genealogical ancestors over the last 1,000 years. There is also substantial regional variation in the number of shared genetic ancestors. For example, there are especially high numbers of common ancestors shared between many eastern populations that date roughly to the migration period (which includes the Slavic and Hunnic expansions into that region). Some of the lowest levels of common ancestry are seen in the Italian and Iberian peninsulas, which may indicate different effects of historical population expansions in these areas and/or more stably structured populations. Population genomic datasets have considerable power to uncover recent demographic history, and will allow a much fuller picture of the close genealogical kinship of individuals across the world. Few of us know our family histories more than a few generations back. It is therefore easy to overlook the fact that we are all distant cousins, related to one another via a vast network of relationships. Here we use genome-wide data from European individuals to investigate these relationships over the past 3,000 years, by looking for long stretches of genome that are shared between pairs of individuals through their inheritance from common genetic ancestors. We quantify this ubiquitous recent common ancestry, showing for instance that even pairs of individuals from opposite ends of Europe share hundreds of genetic common ancestors over this time period. Despite this degree of commonality, there are also striking regional differences. Southeastern Europeans, for example, share large numbers of common ancestors that date roughly to the era of the Slavic and Hunnic expansions around 1,500 years ago, while most common ancestors that Italians share with other populations lived longer than 2,500 years ago. The study of long stretches of shared genetic material promises to uncover rich information about many aspects of recent population history.

Peoples: - | Places: Europe | Topics: Hunnic expansion and Slavic expansion | DNA Type: Autosomal DNA

The Greeks in the West: genetic signatures of the Hellenic colonisation in southern Italy and Sicily

Journal: European Journal of Human Genetics | Year: 2016


Greek colonisation of South Italy and Sicily (Magna Graecia) was a defining event in European cultural history, although the demographic processes and genetic impacts involved have not been systematically investigated. Here, we combine high-resolution surveys of the variability at the uni-parentally inherited Y chromosome and mitochondrial DNA in selected samples of putative source and recipient populations with forward-in-time simulations of alternative demographic models to detect signatures of that impact. Using a subset of haplotypes chosen to represent historical sources, we recover a clear signature of Greek ancestry in East Sicily compatible with the settlement from Euboea during the Archaic Period (eighth to fifth century BCE). We inferred moderate sex-bias in the numbers of individuals involved in the colonisation: a few thousand breeding men and a few hundred breeding women were the estimated number of migrants. Last, we demonstrate that studies aimed at quantifying Hellenic genetic flow by the proportion of specific lineages surviving in present-day populations may be misleading.

Peoples: Sicilians | Places: Euboea, Sicily, and South Italy | Topics: Archaic Period, Greek colonisation, Hellenic, and Sex-bias | DNA Type: mtDNA and Y-DNA

The hare and the tortoise: One small step for four SNPs, one giant leap for SNP-kind

Journal: Forensic Science International: Genetics | Year: 2010


A recently published study has used next-gen sequencing technology to resequence two Y chromosomes separated by 13 generations and discovered four single-base differences in approximately 10Mb DNA, suggesting that the Y chromosome euchromatin accumulates around one mutation per generation. Y-SNPs therefore now offer the best resolution of Y haplotypes and promise to distinguish almost every Y chromosome. This work illustrates the promise of current sequencing technology for forensically relevant applications.

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The Himalayas as a Directional Barrier to Gene Flow

Journal: American Journal of Human Genetics | Year: 2007


High-resolution Y-chromosome haplogroup analyses coupled with Y-short tandem repeat (STR) haplotypes were used to (1) investigate the genetic affinities of three populations from Nepal-including Newar, Tamang, and people from cosmopolitan Kathmandu (referred to as Kathmandu” subsequently)-as well as a collection from Tibet and (2) evaluate whether the Himalayan mountain range represents a geographic barrier for gene flow between the Tibetan plateau and the South Asian subcontinent. The results suggest that the Tibetans and Nepalese are in part descendants of Tibeto-Burman-speaking groups originating from Northeast Asia. All four populations are represented predominantly by haplogroup O3a5-M134-derived chromosomes

Peoples: | Places: | Topics: | DNA Type:

The History of Slavs Inferred from Complete Mitochondrial Genome Sequences

Journal: PLoS ONE | Year: 2013


To shed more light on the processes leading to crystallization of a Slavic identity, we investigated variability of complete mitochondrial genomes belonging to haplogroups H5 and H6 (63 mtDNA genomes) from the populations of Eastern and Western Slavs, including new samples of Poles, Ukrainians and Czechs presented here. Molecular dating implies formation of H5 approximately 11.5–16 thousand years ago (kya) in the areas of southern Europe. Within ancient haplogroup H6, dated at around 15–28 kya, there is a subhaplogroup H6c, which probably survived the last glaciation in Europe and has undergone expansion only 3–4 kya, together with the ancestors of some European groups, including the Slavs, because H6c has been detected in Czechs, Poles and Slovaks. Detailed analysis of complete mtDNAs allowed us to identify a number of lineages that seem specific for Central and Eastern Europe (H5a1f, H5a2, H5a1r, H5a1s, H5b4, H5e1a, H5u1, some subbranches of H5a1a and H6a1a9). Some of them could possibly be traced back to at least ~4 kya, which indicates that some of the ancestors of today’s Slavs (Poles, Czechs, Slovaks, Ukrainians and Russians) inhabited areas of Central and Eastern Europe much earlier than it was estimated on the basis of archaeological and historical data. We also sequenced entire mitochondrial genomes of several non-European lineages (A, C, D, G, L) found in contemporary populations of Poland and Ukraine. The analysis of these haplogroups confirms the presence of Siberian (C5c1, A8a1) and Ashkenazi-specific (L2a1l2a) mtDNA lineages in Slavic populations. Moreover, we were able to pinpoint some lineages which could possibly reflect the relatively recent contacts of Slavs with nomadic Altaic peoples (C4a1a, G2a, D5a2a1a1).

Peoples: Czechs, Eastern Slavs, Poles, Russians, Ukrainians, and Western Slavs | Places: Central Europe and Eastern Europe | Topics: - | DNA Type: mtDNA

The history of the North African mitochondrial DNA haplogroup U6 gene flow into the African, Eurasian and American continents

Journal: BMC Evolutionary Biology | Year: 2014


Peoples: | Places: | Topics: | DNA Type: mtDNA

The history of the Y chromosome in man

Journal: Nature Genetics | Year: 2016


Studies of the Y chromosome over the past few decades have opened a window into the history of our species, through the reconstruction and exploitation of a patrilineal (Y-genealogical) tree based on several hundred single-nucleotide variants (SNVs). A new study validates, refines and extends this tree by incorporating >65,000 Y-linked variants identified in 1,244 men representing worldwide diversity.

Peoples: - | Places: - | Topics: Y-chromosome | DNA Type: Y-DNA and Y-SNP

The human genetic history of East Asia: weaving a complex tapestry

Journal: Current Biology | Year: 2010


East Asia encompasses a wide variety of environments, peoples, cultures and languages. Although this review focuses on East Asia, no geographic region can be considered in isolation in terms of human population history, and migrations to and from East Asia have had a major impact. Here, we review the following topics: the initial colonization of East Asia, the direction of migrations between southeast Asia and northern Asia, the genetic relationships of East Asian hunter-gatherers and the genetic impact of various social practices on East Asian populations. By necessity we focus on insights derived from mitochondrial DNA and/or Y-chromosome data; ongoing and future studies of genome-wide SNP or multi-locus re-sequencing data, combined with the use of simulation, model-based methods to infer demographic parameters, will undoubtedly provide additional insights into the population history of East Asia.

Peoples: - | Places: - | Topics: - | DNA Type: Y-DNA

The human genetic history of South Asia

Journal: Current Biology | Year: 2010


South Asia — comprising India, Pakistan, countries in the sub-Himalayan region and Myanmar — was one of the first geographical regions to have been peopled by modern humans. This region has served as a major route of dispersal to other geographical regions, including southeast Asia. The Indian society comprises tribal, ranked caste, and other populations that are largely endogamous. As a result of evolutionary antiquity and endogamy, populations of India show high genetic differentiation and extensive structuring. Linguistic differences of populations provide the best explanation of genetic differences observed in this region of the world. Within India, consistent with social history, extant populations inhabiting northern regions show closer affinities with Indo-European speaking populations of central Asia that those inhabiting southern regions. Extant southern Indian populations may have been derived from early colonizers arriving from Africa along the southern exit route. The higher-ranked caste populations, who were the torch-bearers of Hindu rituals, show closer affinities with central Asian, Indo-European speaking, populations.

Peoples: | Places: | Topics: | DNA Type:

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