Ancient‐DNA and Genetics

Current projects

Ancient‐DNA studies on microbial and genetic diseases (Leprosy, TB, Osteoporosis)
Human genetics of Stone‐Age Scandinavia

A selection from Stockholm University publication database

• Massive migration from the steppe was a source for Indo-European languages in Europe

  2015. Wolfgang Haak (et al.). Nature 522 (7555), 207-+

  Article

  We generated genome-wide data from 69 Europeans who lived between 8,000-3,000 years ago by enriching ancient DNA libraries for a target set of almost 400,000 polymorphisms. Enrichment of these positions decreases the sequencing required for genome-wide ancient DNA analysis by a median of around 250-fold, allowing us to study an order of magnitude more individuals than previous studies(1-8) and to obtain new insights about the past. We show that the populations of Western and Far Eastern Europe followed opposite trajectories between 8,000-5,000 years ago. At the beginning of the Neolithic period in Europe, similar to 8,000-7,000 years ago, closely related groups of early farmers appeared in Germany, Hungary and Spain, different from indigenous hunter-gatherers, whereas Russia was inhabited by a distinctive population of hunter-gatherers with high affinity to a similar to 24,000-year-old Siberian(6). By similar to 6,000-5,000 years ago, farmers throughout much of Europe had more hunter-gatherer ancestry than their predecessors, but in Russia, the Yamnaya steppe herders of this time were descended not only from the preceding eastern European hunter-gatherers, but also from a population of Near Eastern ancestry. Western and Eastern Europe came into contact similar to 4,500 years ago, as the Late Neolithic Corded Ware people from Germany traced similar to 75% of their ancestry to the Yamnaya, documenting a massive migration into the heartland of Europe from its eastern periphery. This steppe ancestry persisted in all sampled central Europeans until at least similar to 3,000 years ago, and is ubiquitous in present-day Europeans. These results provide support for a steppe origin(9) of at least some of the Indo-European languages of Europe.

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

  2014. Iosif Lazaridis (et al.). Nature 513 (7518), 409-+

  Article

  We sequenced the genomes of a similar to 7,000-year-old farmer from Germany and eight similar to 8,000-year-old hunter-gatherers from Luxembourg and Sweden. We analysed these and other ancient genomes(1-4) 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(3), 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 similar to 44% ancestry from a 'basal Eurasian' population that split before the diversification of other non-African lineages.

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• Ancient-DNA reveals an Asian type of Mycobacterium leprae in medieval Scandinavia

  2013. Christos Economou (et al.). Journal of Archaeological Science 40 (1), 465-470

  Article

  Leprosy is a chronic infection of the skin and peripheral nerves caused by the pathogen Mycobacterium leprae. Its impact on human populations and societies of the past as well as its phylogeographic patterns around the world – at least in modern times – has been well documented. This slow growing bacterium has been shown to exist in distinct ‘SNP types’ that occur in relatively defined parts of the globe. The routes that the disease followed in the past are, however, still uncertain. This study of ancient-DNA typing of archaeological human remains from Sweden dated to early Medieval times provides genetic evidence that a transmission of M. leprae ‘SNP subtype’ 2G – found mainly in Asia – took or had already taken place at that time from the Middle East to Scandinavia. This finding is unique in the history of leprosy in Europe. All human specimens from this continent – both modern and ancient – that have been tested to date showed that the one responsible for the infection strains of M. leprae belong to ‘SNP type’ 3, whereas our results show that there were some European populations that were hosts to bacteria representing ‘SNP type’ 2 of the species as well.

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• Genome-Wide Comparison of Medieval and Modern Mycobacterium leprae

  2013. Verena J. Schuenemann (et al.). Science 341 (6142), 179-183

  Article

  Leprosy was endemic in Europe until the Middle Ages. Using DNA array capture, we have obtained genome sequences of Mycobacterium leprae from skeletons of five medieval leprosy cases from the United Kingdom, Sweden, and Denmark. In one case, the DNA was so well preserved that full de novo assembly of the ancient bacterial genome could be achieved through shotgun sequencing alone. The ancient M. leprae sequences were compared with those of 11 modern strains, representing diverse genotypes and geographic origins. The comparisons revealed remarkable genomic conservation during the past 1000 years, a European origin for leprosy in the Americas, and the presence of an M. leprae genotype in medieval Europe now commonly associated with the Middle East. The exceptional preservation of M. leprae biomarkers, both DNA and mycolic acids, in ancient skeletons has major implications for palaeomicrobiology and human pathogen evolution.

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Show all publications by Christos Economou at Stockholm University