These being the dog days of summer, this particular column will be an exercise in self-indulgence. It’s about my ancestry, so consider yourself forewarned.
As people get older, they often develop a curiosity about ancestry. This typically takes the form of genealogy, tracing the family tree back as far as one can through grandparents, great-grandparents and so forth. But with the advent of DNA testing, there’s the new dimension of deep ancestry – genetic analysis that pushes the story back thousands of years.
I first became aware of it about 10 years ago, courtesy of the book Saxons, Vikings, and Celts (2007) by the English geneticist Bryan Sykes. Drawing on the then-latest evidence available from DNA testing, Sykes set out to explain the genetic roots of the British Isles. And having been born in Ireland to Irish parents, this piqued my interest.
The key to Sykes – and other deep ancestry researchers – detective work lies in the accumulated mutations of genetic markers that have been passed down through the centuries. For paternal ancestry, the key is Y-DNA; for maternal ancestry, it’s mitochondrial DNA.
Y-DNA is continually passed from father to son, but not from father to daughter. Mitochondrial DNA is similarly passed from mother to daughter, but it’s also passed from mother to son for one generation. In practical terms, this means that my DNA would carry evidence of both sides of my deep ancestry. And I could have it tested to see what story it told.
So what did I expect – or hope – to find?
DNA-based research invariably concludes that the ancestral origins of the British Isles are old, particularly in Ireland and Wales. So, probability being what it is, the likelihood was that my distant ancestors had been in situ for thousands of years.
Still, there was a trace of mischievous hope that something more exotic might appear. Having grown up in a family of generally exuberant Irish nationalists, there would be some fun in discovering a non-traditional element in the familial bloodline.
The testing involved selecting a service, providing a sample and having their lab run it through various processes and algorithms. Out of this came a couple of haplogroup assignments – one each for my maternal and paternal ancestry lines.
Without getting technical, let’s just say that haplogroups refer to a genetically identifiable common ancestor. Or as my testing service phrases it, “a family of lineages that share a common ancestor and, therefore, a particular set of mutations.”
What, then, did I find?
Maternally, I belong to haplogroup V, which “traces back to a woman who likely lived during the last peak of the Ice Age.” Surviving the deep freeze in more hospitable surroundings, perhaps Iberia or along the Mediterranean, she established a line whose descendants migrated north and west as the ice receded.
V isn’t one of Ireland’s most common maternal lineages – current rough estimates put it in the vicinity of four percent. Not exotic then, but definitely towards the rarer end of the spectrum.
The situation on the paternal side is a different matter entirely.
I’m an R-L21, which is a descendant branch of R-M269, the latter being the most common haplogroup on Europe’s Atlantic seaboard and the dominant one in the British Isles. In Ireland, R-M269 accounts for over 80 percent of males, the overwhelming bulk of whom are R-L21.
R-L21’s unique genetic marker was identified in 2005, and some research suggests it emerged in Cornwall and Devon between 4,000 and 5,000 years ago. From there, it spread through the British Isles, including across the sea to Ireland.
This theory links R-L21’s Irish dominance to a catastrophic event around 100 BC when – through some combination of extreme weather, plague, invasion and warfare – Ireland’s earlier male line was decimated and largely replaced by my ancestors.
Nothing, it seems, is sacred. I can’t even claim to be indigenously Irish!
Other than being a bit of fun, does research into genetically-based deep ancestry have broader implications?
It might encourage people to focus on their historic tribal roots, which could have divisive ramifications.
Then again, multiculturalism’s propensity towards identity politics can do the same thing. And if we insist on genuflecting towards one, we can surely cope with the other.
Pat Murphy casts a history buff’s eye at the goings-on in our world. Never cynical – well perhaps a little bit.