Genetic Analysis of the Thomas Shannon lineage YDNA

Basic points

  1. Our YDNA is a rare type of the most common western European paternal genetic lineages.
  2. It has been associated with our surname for at least 800 years in a Scottish Lowland cultural context, but is atypical for that region.
  3. Its most distant branches are more closely related to populations in North central Europe but a small minority population even there.
  4. Clusters in American families who descend from a Scots/Scots-Irish cultural context.  Also found in at least one family still in Scotland.

Historic analysis of our paternal lineage since the Bronze Age by YDNA branching events: 

    • Mutation R-S1194 (~3000BC) :  Migration from the steppes region north of the Black sea into central Europe as part of an early Bronze Age, proto-Indo-European speaking tribal society.
    • Mutation R-S14328 (~2800BC): Establishment of some cultural tribal base in central Europe
    • Mutation R-Y23555 (~1850 BC) Long period of stability in some location followed by sudden violence and collapse, survivors integrating into tribal societies of the lower Rhine River region of Northern Europe.  Conquest by Romans and integration into the Roman military then stationing along Hadrian’s Wall on the northern British frontier.
    • Mutation R-Y23202 (~ 400 AD) Collapse of Rome and integration into early Medieval Scottish political groups.  This is the period when Roman forces leave Britain for the last time and the rise of Romano-British tribal groups. This same mutation is also carried by a large Matthews family with possible connections back to Wales.  This suggests some sort of strong association with the early dynastic post-Roman families of Northern Britain which are known to have left descendants in both Southern Scotland and Wales. 
    • Mutation R-E306: (~900 AD) Cultural adaption to Gaelic speaking traders from Ireland in the Galloway region of Scotland. The name ‘Shannon’ adopted sometime after this, probably meaning ‘Old’ (‘sean’ in Gaelic) family (‘Ashennan’ perhaps interprets as ‘a descendant of the family that has owned this area for a long time’, i.e. ‘the old ones’). This mutation is also carried by a Stewart family and McCoy families, names typically associated with Scotland.
    • Mutation R-Y34202 (~1300 AD) Survival as a family of some local prominence in the area of Kirkcudbrightshire. This would be the era of the Scottish wars of independence (‘Braveheart’).   At least two separate Shannon lineages carry this mutation, along with a large number of Reeds and a Ferguson family, all with strong association with Southern Scotland.   This establishes that our surname probably existed prior to this date as an established family but after the ~900AD date.  These dates bracket the entire period of the Galloway region of Scotland going from Brythonic speaking to Gaelic Speaking to Scots/English speaking.
    • Mutation R-Y34201 (~1750 AD). Loss of ancestral lands and Integration into the early modern commodities economy of the British Empire. Migration to the American South and integration into slave based agricultural economy, Revolution, Civil War, economic collapse and ultimate integration into post-modern American society with loss of ethnic and cultural identity.   This mutation is verified to be carried by at least two Shannon lineages and one McGregor line.  There is probably another Shannon line that has not yet performed deep Y testing.  

    Detailed Analysis

    The Y Chromosome is passed directly from father to son with no admixture with other DNA. Mutations within the YDNA can therefore serve as markers recording the history of a paternal lineage. These mutations are given coded designations by the research labs that discover them.

    All documented male descendants of Thomas Shannon (1730-1794) share a yDNA marker (R-Y34201…R-S1194).  This is related to the most common yDNA types of western Europe (R-P312/R-U106) but is a rare type carried by less than one percent of that population tested so far.  Ours is the only Shannon lineage in the American South with this particular rare yDNA discovered so far.  There are three other Shannon lines with this same marker known in the US, but all the others remained in the North.

    The two most distant Shannon lines with this yDNA indicate a common ancestor who lived about 800 years ago.  The closest Shannon match is between our line and another Shannon family that migrated across the Midwest and lives today in Northern California.  Our distance to this line is close to the time of migration (~300 years) which might indicate a common family relationship at that time.   However, the difference in migratory and economic decisions made between these two lines after migration to the colonies makes me believe they arrived under very different circumstances so had probably been separated by at least a generation or two before migration.    

    Our closest yDNA match outside of the Thomas Shannon lineage is a McGregor family with no family history of ever leaving Scotland.   Our distance to this line is also estimated at roughly 300 years, or about the same time as the migration of Thomas.   How this happened is a true mystery, but somehow this McGregor lineage has a close common ancestor with our Thomas Shannon.  In fact, it is possible that Thomas himself is the common ancestor.  Did our Thomas leave a child behind when he migrated who was adopted into a McGregor family in Scotland?      

    Regardless of our Gaelic name, we do not have any strong paternal association with the well known genetic lineages of Ireland.   It appears that we descend from a male lineage most likely native to Southern Scotland since at least the very early medieval period (400 AD).  We most likely acquired a Gaelic name when that region became Gaelic speaking as England was forming to the south and Ireland became the most important cultural contact for the populations in northern Britain facing the Irish sea.  So, in our case, even though there appears to be a quite ancient association between the surname and the yDNA, the name itself seems to be more of a linguistic coincidence than evidence of any deep Irish ancestry.

    Beyond Scotland, our next closest yDNA kin groups are found in the lower Rhine region of North central Europe dating back to pre-Roman times and Iron Age tribal societies. Distant branches of this yDNA are spread thinly from Southern England, across western Scandinavia and in central Europe.  However, the only areas of relative concentration are in western Germany, the lower Rhine regions and in Southern Scotland.   This would tend to suggest an ancient history of a male population that was conquered by the Romans during their conquest of the Belgic regions of Gaul, and later becoming incorporated into the Roman army as auxiliary troops for the occupation of Northern Britain, which was a well-known official policy of the Roman Imperial government.   In this way, young men who might have otherwise joined anti-Roman rebellions in their conquered homelands, instead become incorporated into the Roman military to strengthen their control of other regions.

    Remains of an individual carrying our rare YDNA has been found in an old Roman Cemetery at a fort located on the coast of the Netherlands. This fort was a staging post for the occupation of Roman Britain. Most of those stationed there were recruited from the local population. This establishes a direct connection between our genetic lineage and the known historic process of service in the Roman army by assimilated populations. When associated with a YDNA branching event for our paternal lineage in Northern Britain at precisely the time of Roman withdrawal from Britain (c. 407 AD) and the rise of Romano-British families, this serves to support the hypothesis that our ancestral paternal line was introduced into that area in some capacity within Roman military service.

    Our DNA is least common in areas most heavily affected by later Medieval population movements into Britain by Scandinavians, Irish or Anglo Saxon settlers.  It is most common in areas these populations settled the least. This would tend to suggest that they arrived prior to the later large scale Medieval migrations from elsewhere.

    The name Shannon/Shennan/Ashennan, etc, has a very long history in the region around Tongland in Kirkcudbrightshire Scotland.  Families of this name held lands in that region since at least 1376.   This is where the name Shannon by various spellings is most commonly found in historic records even compared to Ireland. The correspondence between the current age estimate of our yDNA and the first documented occurrence of the name in this region seems very compelling.  Both are in the 700-800 year range.  This is where I believe our family was probably originally from, but so far have no documented proof.   All known families of this name that can document an ancestry back to that area have stubbornly refused all requests for genetic testing.   Still, given the age of our YDNA and how long the name has existed in that region, it is a reasonable assumption that this was where we became Shannons possibly as early as the 10th century as Gaelic came to dominate that region for several centuries afterwards.