Mrs. Green Genes

I'm always in the mood to write about (talk about, bore everyone about) using DNA to find missing ancestors from the past few hundred years. Unfortunately, I always seem to get so mired in discussing The Ethnicity Problem that I usually never bother finishing the post.

The Ethnicity Problem is as follows: Many genealogists (from the serious-serious with decades of experience to the "so new I'm still spelling genealogy with an /o/ in the middle") are now taking DNA tests to see what the test will say about their ethnicity. However, these genealogists don't realize that the little geography chart with percentages is but a puny crumb in the rich layer cake that is their DNA test results. Nay (dramatic arm wave!), it is the negligent scatter of dry crumbs next to the cake, ready to be wiped away.

Sweep them! Sweep those crumbs away, I say!

A Michelin-class dessert is set before these genealogists, and yet they're barely glancing at the organic, fair-trade cocoa dusting, they're scraping aside the filigree'd frosting, they're ignoring the berry-six-ways gelee. Instead, they're briefly hovering their faces near enough to the plate that their tongues might dab at those wayward crumbs.

These genealogists (and I really mean genealogists, not other test-takers) don't realize they're sitting on the power to find MANY of their missing ancestors. (Even the most thorough family trees are missing about 65% of the ancestors than an autosomal test can theoretically identify.) If only the three major DNA companies would use their marketing power to push their real product.

BUT. This time I'm going to publish my post, so let's not dwell on that.

Even though that ethnicity information is mostly useless for genealogical purposes, it's fun.

Today is Saint Patrick's Day. Let's have some fun. 

(I apologize for the inclusive "let's." I'm going to have some fun, and for everyone else, here's a video of Bonnie Raitt, Irishing it up with A Stor Mo Chroi.)

How Irish am I? We have to come back to how genealogy has many faces: cultural, social, historical, biological.

Culturally, I'm barely Irish. Sure, I grew up with family stories that said we were Irish. My mother could repeat some expressions that her great-grandmother used. My great-grand-uncle, born on Saint Paddy's Day and called Patrick, played it up all his life to be the typical "more Irish than the Irish" American of Irish descent. But it would take a seasoned (and tenured, and possibly somewhat psychic) Hibernian anthropologist to interview me as a child, circa 1980, and say, "Oh yes, I detect some Irish influence there."

Socially, I'm a bit more Irish. I've sought out those known Irish connections. Visited Ireland. Studied the Irish language for many years, optimistic romantic that I am. When I think about the "social" side of genealogy, I think about an adult's chosen identity. A person who pursues the family history of their adoptive parents might be said to be taking a cultural approach, but a person who pursues the family history of their best friends who are now treated as family is taking a more social view of how their lives are influenced by family history. You might also say that looking into the family history of a spouse is a social approach.

The social side of family history isn't so much about who bred you or raised you, but whose history helps form your current identity.

Anyway, I'm not all that socially Irish. I'd be embarrassed to tell you the last time I had a creamy, boggy Guinness on tap. (But I will tell you if you put one in my hand.)

Historically, I'm Irish, but from where I'm sitting, it's six generations until Mary Susan Smith's unknown father is born in Ireland, seven generations until Hannah Riggs' unknown mother crosses the Atlantic, and eight generations until Absalom Carroll emigrates from Cork. My tree is complete for the five generations before me, and DNA seems to be backing most if not all of it, so no shamrocks are going to appear any closer than that.

I may have other Irish lines within the time period that one can do genealogy - I'm certain I do - and not know it. But, if I were the sort of person who wants to say "I'm X-percent Irish," I'd have to assume a boorish expression and monotone the following:

"Ignoring all of those ancestors at the eighth generation whose identities I don't know and who could be 100% Irish, and ignoring the possibility that my known Irish ancestors could've been the children of Turkish immigrants who had only just moved to Ireland, and ignoring those common cousin marriages that skew the number of ancestors we actually have, then I'm about 6.64% Irish."

But what does that tell anyone, though? (And really, with all those factors, I may as well make any number up.)

Save the percentages for an easy way to describe your cultural/social inheritence from your parents and grandparents. After that, it's just too murky to try to use accurate math.

But again, those DNA ethnicity breakdowns are fun. So let's think biologically!

People have this cute idea that we each inherit 50% of the DNA from every generation above us, and that the 50% is neatly divided at ever level. "So," they say, "if my great-grandmother was Cherokee" (because it's always Cherokee) "then I should see 1/8 Cherokee on my DNA results."

Maybe. Or you could see nothing. Either is entirely likely.

Anyone who has DNA-tested three generations of a family can tell you that all bets are off after your parents each contribute their 50%.

Yes, I inherited 50% of my mother's DNA, but which 50%? If you think it's equally 25% from each of her parents, ha. If you think half of each ethnicity that was passed down to her made it to me, HA!

Here's a chart from FTDNA comparing me to my Nonna (maternal grandmother):


The yellow-y bars are where I match my grandmother. The blue bars are where I match my grandfather. (Ignore the grey bars.)

Look at chromosomes 10, 11, and 12. Nonna was a DNA bully!

When actually crunching the numbers, the percentage contributed to my DNA makeup from my maternal grandparents works out to 55%/45% overall in favour of my grandmother, but it could have just as easily been 70%/30% or 95%/5%.

Which genes a mother passes down to her child are random. Maybe you'll get grandma's, maybe you'll get grandpa's. This is why it's important to DNA-test siblings when you can't test a parent. They will almost certainly have information that you didn't inherit.

(I really got lucky on the X chromosome. That tiny bit of yellow means that most of my maternal X chromosome comes from my grandfather's mother. Any X cousin matches I get on my maternal side will be a great help in solving the riddles behind my Granny's life.)

FTDNA has terrible ethnicity prediction (although they're working on it), so I can't show you from this chart how much of the "Irishness" my grandmother passed along to me. (Even if I could, their website is as slow as narcoleptic turtle this week.) 23andMe has the best chromosome comparison charts, but Nonna didn't test there. GEDmatch is very useful but not quite pretty/easy enough to play with for today's funsies. (Darn me and my narrow blog layout.)

However, Nonna did test at Ancestry. They don't do a by-chromosome breakdown, but they do attempt to detect ancestry from the geographical area known today as Ireland. (Describing results by modern country borders and not by population or zone is a bit controversial, but we'll ignore that today.)

Below is a chart showing the four "Ireland" results for the five tests my family has done at Ancestry. They are ordered from lowest to highest. Which belongs to which person?


Some hints:

  • Two of my three known Irish ancestors - the two most recent ones - are on Dad's side. (But not on my great-aunt's side.) The two Irish ancestors are also Uncle Pat's ancestors, so it's that branch of the family that taught most of us that we were Irish.
  • My paternal great-aunt's side has Irish surnames but no documented Irish records.
  • My maternal grandmother's side has Irish stories from recent ancestors but no documented Irish records.
  • My mother's paternal side has the most distant known Irish ancestor.
  • Obviously, one of us did not end up with any Irish DNA (by Ancestry's standards) at all.

Now some mindless spacing dots so you won't see the answer without trying to guess. (If you've read this far, you have to pretend to care):












My paternal great-aunt was the one with no Irish DNA. Does it change how I look at some of the surnames that we share? No, but it reminds me not to make assumptions.

My father, with the most recent Irish ancestors, plus the most family tradition about our Irishness (there's even an Irish-long tale about our Irish ancestor who had to take his English wife's name), is the person with 1% Irish.

My grandmother, whose grandmother used to tell my mother stories and speak with what people thought was a lilt plus use expressions like "faith and begorra" (and who named my great-grandmother a very Irish-y "Nora") is 9% Irish.

Now, if it were me with the 26% Irish, that would be a story: "Woman gets Irish DNA Injections at Secret Swiss Clinic!" It is, as you can guess, my mother who Ancestry says is 26% Irish, the person with the most distant Irish ancestor, and the one with no Irish stories from her father's side. Ha!

(And in case you missed it above, DNA has proven or at least strongly suggested that I probably don't have any "dastardly milkman events" for at least six generations.)

How much of Mom's 26% comes from my grandmother's 9% (if any!) is something I could squeeze out of GEDmatch, but it's late, so no. If my grandfather had tested, I can assume that Ancestry would've shown him with at least 17% Irish.

That leaves me at an alleged 17% of genetic evidence for Irish ancestry, a few percent points more Irish than if you add Mom and Dad's percentages together then cut them in half.

You could play with these stats all day and make them sing all kinds of tunes. For example:

23andMe lumps British and Irish together. If I look at how they report my parents' ethnicity (in speculative mode, which seems closest to what Ancestry does), Mom is 76% British and Irish, Dad is 51% B&I, and I am 64%. If I combine British and Irish numbers at, it's 79% for Mom, 77% for Dad, and 58% for me.

Mom and I have same-ish numbers at the two companies, but Dad gains 26% British at Ancestry. (If I change 23andMe to standard mode, the numbers for all three drop dramatically to under 35%.)

Hopefully that makes some sort of point about how using DNA to look at ethnicity means staying open-minded. The percentages change depending on the tool (consider GEDmatch - they host at least a dozen ways to measure these things), but patterns tend to stick around. Wherever I look, Mom has a solid chunk of Irish, I have somewhat less, and Dad has far less compared to Mom.

But in the end...

So give us kisses, not pinches, for 'tis green I'll be wearing tonight, to be sure!

Or, in Irish: Mar sin, a thabhairt dúinn póga, ní luíonn, le haghaidh tá sé glas go mbainfidh mé a bheith ag caitheamh anocht, a bheith cinnte!

(Yeah, I used Google Translate. I haven't lenited or eclipsed an emerald noun in years. Where's that Guinness?)

17 March 2014 |






Carnival Elation (2009)
Carnival Splendor (2009)
Carnival Spirit (2010)
Carnival Spirit (2011)
Carnival Splendor (2011)
Norwegian Pearl to Alaska (2012)