Wednesday, April 24, 2019

Y-DNA haplogroup

I don't know my Y-DNA haplogroup.  I could take the 23andme test, or one of several others that gives me genomic information, but in reality, my ancestry isn't very mysterious to me, and I don't want to spend the bucks to do a test only to be told what I already know, plus something that's kind of esoteric, but which I'm curious about, like my haplogroup assignment.

That said, I can limit my likely haplogroups down to half a dozen closely related variants easily enough.  My ancestry is mostly English and some Scottish.  I also have some Portuguese ancestry through my paternal grandmother's side of the family, but because it's my paternal grandmother, it wouldn't have given me either a Y-DNA or an mtDNA haplogroup.  For that, I need look only to my British ancestry.  The possibilities are, therefore:
  • R1a-L664, which is a Northwestern European haplogroup associated with the arrival of the Corded Ware horizon to the shores of Northern Europe.  It is (relatively speaking) slightly common today in areas in which the Corded Ware or its derivatives (such as Dutch Bell Beaker) settled, including Western Germany, the Low Countries and the British Isles.  In general, R1a is much more associated with Eastern Europe than Western Europe, but it still is present from this ancient invasion.
  • R1a-Z284 is a specifically Scandinavian subclade.  Its epicenter is in central Norway, but it also appears in places where the Vikings settled, including England and Scotland.  Also, my Y-DNA heritage can be traced, of course, through the male line, and my male line does back to the Norman invasion of England in 1066 before we lose track of it somewhere in Normandy.  The Normans were, of course, also Vikings who had settled in France and taken local Frankish wives.  Although at a total genome level, I don't associate much with the Vikings but rather with the Anglo-Saxons and the Scottish, at the Y-DNA level, there's a very good chance that I have a Viking/Norman haplogroup.  That said, the R1a haplogroups are themselves relatively rare in England and by extension in areas settled by the former English, like America (and Australia, New Zealand, and South Africa.)  They make up a significant plurality, but R1b is much more common.
  • R1b-L21 is the so-called "Celtic" subclade.  It actually dates to before the formation of the Celts, and can be found in the Bronze Age Unetice culture, which is considered by most to have been at a level where Celtic, Italic and Germanic had yet to completely split from each other (Celtic and Italic more in the southern and Central Europe, Germanic after moving north, hybridizing with the remnant Corded Ware population to form the Nordic Bronze Age, which eventually became Germanic.)  While I no doubt have many ancestors who've had this genetic clade, it's probably unlikely that I do myself.  It's not out of the question, but unlikely, based on what I know of my paternal line, which is how Y-DNA is passed on.  By the same token, it's possible although even more unlikely that I have the related R1b-S28 subclade.  This appears in small numbers in the British Isles, but it mostly associated with the traditional Gallic expansion of the Celts and is most common in Alpine Northern Italy, Switzerland, a corner of southern Germany, and the French Riviera coastline, while the L21 clade is most common western Ireland, Scotland, some of Wales and Cornwall and Brittany, although in much smaller percentages throughout the British Isles.
  • R1b-S21 is the Y-DNA haplogroup that I consider most likely by a significant margin.  It's a marker associated with the Germanic language group overall, and is quite common in areas with heavy Germanic settlement, including (naturally) the Nordic Bronze Age territory.  It is a derivative clade from the Unetice group that helped create the Germanic languages in the first place, it was brought by the Franks to the Low Countries and much of northern France (including, especially Normandy), the Anglo-Saxons made it incredibly common in England, and it's also incredibly common in much of Germany, Austria and Scandinavia.  In fact, I have multiple avenues by which this clade could have come with my ancestors to England and from there to America. 
  • I didn't think it likely, at first, that I'd have an I1-DF29+ or I1a under the older classification scheme, clade, but given that my Y-DNA is specifically Norman (most likely) then the odds actually rise compared to, say, an Anglo-Saxon or Lowland Scottish dude.  The I1 haplogroup is the only haplogroup in this assemblage that isn't specifically associated with the arrival of warlike Indo-European males through the Corded Ware or Yamnaya horizons or their later derivatives, but is rather a native hunter-gatherer clade that was common in prehistoric cultures like TRB, Ertebølle, and Globular Amphora.  The peopling of Europe in prehistory is interesting.  A big wave of Neolithic farmers invaded Europe from the south (during the Neolithic Age, obviously) and replaced much of the hunter-gatherer genetics that previously had been there, which is why southern, Mediterranean Europe still looks phenotypically very different from Northern Europe even today.  As the latitude increased however, this replacement waned.  The farther north you go, the greater the preponderance of hunter-gatherer DNA remained.  And cultures like TRB and Globular Amphora may well have been invasive to their historical range from the west and north, even.  When the Indo-Europeans came, they largely replaced much of the Y-DNA haplogroups associated with the farmers, although the mtDNA haplogroups continued.  (In other words, they were much more successful than the farmers with the ladies, and they passed down their genes while the farmer men didn't, being forced to see their women fall into the arms of the invaders.  This may have been a very violent affair associated with the killing of the men and the Sabine women-like rape and capture of the local girls, or it may have been relatively peaceful where the newcomers were simply more economically successful which in turn led to being more procreatively successful.  Most likely elements of both persisted depending on the time and place.)  But again, in the northern areas, this didn't happen nearly as much, and the equally war-like GAC descended more from the Western and Scandinavian hunter-gatherers held their own with the incoming post-Yamnaya folks and merged with them in many areas to contribute a significant number of male lineages to the Corded Ware and subsequent populations of the area.  I1 is especially common still in Scandinavia, but all of northern Europe still has traces of it.  Most of the Germanic territory it's much more than a trace, making up a significant plurality of the population.  This has led to the hypothesis, first proposed on linguistic grounds but now strengthened by genetic ones, that the Germanic languages in particular formed as a three-way hybrid; first, the first wave of Indo-Europeanization (mostly R1a Corded Ware, possibly speaking a satem language distantly related to what later emerged as Balto-Slavic) hybridized with a local hunter-gather and mixed farming population of equally war-like people like GAC, which were once believed to have been "Indo-Europeanized" according to the original version of Gimbutas' kurgan hypothesis.  Genetic research has largely removed that interpretation from play, but clearly the GAC was a militarized and warlike culture, which may account for its durability in the face of Indo-European invasion, and the subsequent persistence of Y-DNA lines that are associated with it in the subsequent post-I-E cultures.  Later, a second wave of R1b Indo-Europeans from the Unetice horizon spread over the same area bringing with them an Indo-European centum language.  Anyway, the point of all of this is that I1 is actually quite possible, especially given its relatively high occurrence in Scandinavian ancestries, like that of the Normans.
Anyway, in conclusion, R1b-S21 is by far the most likely Y-DNA haplogroup to which I belong, but I1 and R1a-Z284 are also possibilities.  All of the other ones I highlighted are very remote possibilities, and I'd be very surprised to have them pop up.

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