The Historical Genetics of the Cotentin Peninsula

The Historical Genetics of the Cotentin Peninsula (Manche, Normandy): A Detailed Case-Study


This project is being carried out by Dr Richard Jones and Dr Turi King, in partnership with Prof Pierre Bauduin. It is a collaboration between the University of Leicester (UK) and the Centre de Recherches Archéologiques et Historiques Anciennes et Médiévales UMP6273 (CNRS/UCBN), Université de Caen Basse-Normandie (France).  It unites two significant on-going research strands in these institutions: at Leicester, ‘The Impact of Diaspora on the Making of Britain’ funded by the Leverhulme Trust; and in Caen: ‘Diasporas, identitiés et transfers culturels dans les mondes normands médiévaux


This project is being conducted with the authorization of the La Cellule de Bioéthique du Ministère d’Education Nationale et d’Enseignement Supérieur et de la Recherche IE-2014-777.  The project has ethical approval from the University of Leicester.  The project is conducted in accordance with the UK Data Protection Act 1998.  The University of Leicester is a registered institution operating in accordance with the protocols of the UK Information Commissioner’s Office.

The legal status of this project is summarized in this statement from the CNRS Direction des Affaires Juridiques:

‘Le traitement de données personnelles (salive) mis en œuvre dans le cadre du projet scientifique n’est pas soumis aux dispositions de la loi française, mais à celles de loi la anglaise. En effet, c’est l’université de Leicester (partenaire du CRAHAM) qui est responsable de ce traitement.

L’université de Leicester a réalisé les démarches nécessaires auprès de l’ICO (Information Commissioner’s Office, équivalent de la CNIL au Royaume Uni) pour la réalisation de ce projet.

Le projet de recherche prévoit une analyse des échantillons salivaires prélevés sur le territoire anglais. Toute exportation d’échantillons provenant du corps humain doit faire l’objet d’un accord. Cette obligation est une exception française au principe de libre-circulation des biens. Cette autorisation a été obtenue auprès de la cellule de bioéthique du MENESR.’


The first millennium AD witnessed significant movements of people across and between continental Europe, Scandinavia, Britain and Ireland. These led to territorial reorganization, the creation of new polities, and in some places, the emergence of unified states, as well as a raft of social, economic, cultural, and linguistic developments.  Many of these folk migrations and periods of colonization and settlement are attested in the historical record and some can be traced through the archaeological record. Important questions remain, however, regarding the scale and timing of these diaspora.

Genetics offers a new way of approaching these issues in a period when both the historical and archaeological records are at best fragmentary.  Excitingly, this science has already begun to offer important insights that would otherwise be difficult to determine from the written and physical evidence alone.  This has been made possible through the multiplication of detailed local studies of the genetic make-up of modern populations which reveal significant variations in genetic signatures at local and regional scale.  Put together, these offer a chance to assess similarities and divergences at a pan-European scale and account for these through known or previously unrecognised historical processes.

Our project targets Normandy, a region which currently lacks a major study of historical genetics, and which thus cannot furnish comparative data to be examined alongside existing datasets from Brittany, Britain, Ireland, the Low Countries, Frisia, and Scandinavia. This gap in our knowledge is all the more critical given Normandy’s unique yet shared history with its neighbouring territories.  In particular, the Scandinavian take-over and colonization of parts of the duchy during the ninth and tenth centuries remains poorly understood.  Although historically attested, archaeological evidence for Viking settlement has proven elusive to identify.  Yet in certain parts of Normandy, notably in Seine-Maritime (Haute-Normandie) and Manche (Basse-Normandie), place-names of Norse or Danish origin appear to point to large-scale settlement, a scenario also seemingly reflected in the number of Scandinavian surnames which have survived in these areas.

Genetics offers an alternative way to gauge not just the scale of Scandinavian colonization in Normandy, but potentially to elucidate—through comparison with other datasets—the processes by which this occurred: it is not known, for example, whether Scandinavian settlers came directly to Normandy from their homelands or whether they settled indirectly from the English Danelaw or other Viking territories around the Irish Sea.

While the focus of this survey of modern DNA targets the period of Viking settlement in Normandy, and in the Cotentin Peninsula more precisely, the programme has the additional potential to address a whole range of other historical questions pertinent to the specific region and the wider history of early medieval Europe including the ‘Germanic’ contribution to the region’s genetics following the settlement of Germanic tribes in the fifth century; and given its brief political annexation and geographic proximity to Brittany, the ‘Celtic’ contribution in western Normandy.  Given these, together with its Gallo-Roman heritage, the Cotentin offers an almost unique opportunity to examine some of the most important diaspora of the first millennium AD which led to the making of modern France and Europe.


This programme focuses specifically on this formative phase in the creation of Normandy where it forms part of The Viking DNA project. Since the Early Middle Ages there has been population growth and movement which has acted to blur the genetic signal of this earlier period. Two methods have been successfully developed elsewhere (e.g. on the Wirral Peninsula in north-west England; in Yorkshire; and in Ireland) to sample individuals who are more likely to have deeper ancestry in a given area.

The first of these is surname-based sampling.  Heritable surnames have been present in France since the early eleventh century and therefore men bearing old surnames from the region have been asked to take part. We are particularly interested in surnames containing elements which might betray Scandinavian heritage, names such as (but not limited to) Anquetil, Dutot, Equilbec, Gonfray, Ingouf, Lanfry, Osouf, Osmont, Quetel, Tougis, Tostain, and Raoult and their many variants.  ‘Non-Scandinavian’ surnames are of interest too, particularly those found in the historical record which exhibit a strong regional association with the Cotentin peninsula.

The second method is geographic-based sampling.  We have been keen to make contact with individuals whose four grandparents were born and lived within an 50 kilometre radius of their current abode. Such family stability in a particular geographic location, going back over three generations, has been shown in other studies to be an effective way of tracing DNA markers back across much greater expanses of time.  In England it is often very difficult to find individuals who meet this criteria.  In France, by contrast, familial ties to a particular commune or group of neighbouring communes over several generations remains common.  For this project all our donors meet this criteria.


We have taken samples from c. 100 men who fulfil one or both of the sampling criteria.  Because surnames are paternally inherited, only men have been asked to take part.  This is a methodological issue rather than a historical one: we are aware that women played a significant role in the Scandinavian diaspora.  Over and above our interest in surnames, men carry both the Y-Chromosome (past from father to son) and Mitochondrial DNA (passed from mother to both sons and daughters).  Consequently sampling males permits the collection and analysis of these two dimensions of human DNA to be most efficiently achieved.

This study will use a model established by the Wellcome Trust-funded People of the British Isles project to analyse the results.  DNA will be extracted from the saliva and whole genome SNP typing carried out using the Affymetrix Genome-Wide Human SNP array. Whole genome SNP typing allows us to ascertain the DNA sequence that an individual carries at ~1 million sites simultaneously across the genome and examine genetic variability in and between populations. This is a method which provides a powerful way of understanding genetic ancestry and has been used very successfully in studies of the population genetics of modern populations in Europe. The 'old Normandy' population data-set will undergo population genetic analysis alongside British, Norwegian, Danish and other European datasets.

When the research is published, we will ensure that it is not possible to identify individuals who took part in the study.

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