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Mapping co-ancestry connections between genome of Medieval indiv, & modern Europeans

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  • Mapping co-ancestry connections between genome of Medieval indiv, & modern Europeans

    Full title: "Mapping co-ancestry connections between the genome of a Medieval individual and modern Europeans"

    Historical genetic links among similar populations can be difficult to establish. Identity by descent (IBD) analyses find genomic blocks that represent direct genealogical relationships among individuals. However, this method has rarely been applied to ancient genomes because IBD stretches are progressively fragmented by recombination and thus not recognizable after few tens of generations. To explore such genealogical relationships, we estimated long IBD blocks among modern Europeans, generating networks to uncover the genetic structures. We found that Basques, Sardinians, Icelanders and Orcadians form, each of them, highly intraconnected sub-clusters in a European network, indicating dense genealogical links within small, isolated populations. We also exposed individual genealogical links -such as the connection between one Basque and one Icelandic individual- that cannot be uncovered with other, widely used population genetics methods such as PCA or ADMIXTURE. Moreover, using ancient DNA technology we sequenced a Late Medieval individual (Barcelona, Spain) to high genomic coverage and identified IBD blocks shared between her and modern Europeans. The Medieval IBD blocks are statistically overrepresented only in modern Spaniards, which is the geographically closest population. This approach can be used to produce a fine-scale reflection of shared ancestry across different populations of the world, offering a direct genetic link from the past to the present.

  • #2
    Thanks for posting.

    Looks like a very curious article which I might need to spend some time with.


    • #3
      From the abstract, I see a hint of things to come -- perhaps a path to a new view of "ethnic origins" based on historical rather than modern genetic data. It starts with one medieval individual. But the method and the conclusions will have to be replicated by others, and it won't be helpful without a huge expansion to include thousands of well-documented medieval skeletons, and especially, those whose identities can be established. What I would most like to see is a concentration on late medieval Europe, say the 13th through 15th Centuries, the period where we can first document the ancestry of many modern families in records of daily life, such as feudal rent assessments, donations to the local churches, contracts, etc. However, it seems to me a full forensic analysis is required, in order to connect the physical indicators (including isotopic analysis that establishes geographic origins) with the genetic data. The level of effort required is going to be huge.