Monday, June 13, 2016
Me and 23: Confessions of a Genome Junky
by Carol A. Westbrook
I have 23 first cousins. Me and my 23 cousins are not particularly interested in our genealogy or our genetics. We know our roots: Polish ancestry via our common grandparents, and Polish on both sides for me; pictured here are my paternal grandparents. We know that we will eventually succumb to cardiovascular disease (heart, stroke or high blood pressure), while no other serious diseases run in the family. And we all look alike, as you can see from this picture of a recent cousins-only reunion.
In truth, I don't have 23 first cousins, I have 30. I have nine cousins on my mother's side. I have twenty-one on my father's side, most of whom were at the reunion in the picture, and all of whom are descended from our common Polish grandparents, Eva and Marek Garstka, pictured at the top of this article. I use the phrase "23 cousins" figuratively, as it is a convenient segue to the topic of the DNA test service, 23andMe. Initially I was dismissive of this genealogy-based service because, like most of my cousins, I felt that there was nothing to learn from genetic testing. I know my medical heritage, I don't need to confirm that I was 100% Polish, and I, for one, was not interested in using this service to find any more relatives. I have too many already.
I had been resisting 23andMe for another reason: because I am a genome junky, and I am on the wagon. I love having my DNA tested. I feel a kinship with DNA testing because I did research in the US Human Genome Program for twenty years of my career. I had had my own genome sequenced by Illumina, about 2 years ago, at considerable expense. (See my post of April 23, 2014, My Genome Report Card). I realized then that I had to stop spending money on DNA tests and have sworn them off since then.
What changed my mind was my husband. The discussion went like this,
"You have no culture. You are truly Neanderthal," he said.
"No, you are more Neanderthal than I am, " I responded.
"Okay, prove it," he countered.
So we both ordered the 23andMe kits.
We sent in our money and got the kit in the overnight mail. We collected out spit in the tubes and mailed it in. A few weeks later we were each notified by email that our results were available, so we logged into the secure web site and went straight to the ancestry section on "Neanderthal DNA."
Yep. I was right. I he was more Neanderthal than I was, his 295 cave-man genes to my 279. A slight margin, but not enough, he pointed out, to secure the nomination.
But there was more to learn from 23andMe.
Not surprisingly, I did not carry genes for any of 36 recessive diseases tested by 23andMe, most of which are rare diseases of childhood. I already knew this from my Illumina sequence. Unlike Illumina, though, 23andMe does not test for serious dominant diseases that show up later in life, such as breast cancer, Lou Gehrig's Disease, or Huntington's Disease.
23andMe tests for traits, and accurately predicted that I have light skin with minimal freckling, blonde, straight hair, and blue eyes, and that I don't have a cleft chin, dimples, or a widow's peak. It also reported that I was likely to be a heavy consumer of caffeine and a runner, but not a deep sleeper. All true. I can taste bitter, I can smell asparagus, I prefer salty snacks to sweet, and don't flush with alcohol (though I flush for other reasons). I have the gene for lactose intolerance, though this was puzzling because I'm not bothered by dairy products, which I consume daily.
Many people have found long-lost relatives through 23AndMe, including orphans, people sired by sperm donors, and people whose real father is not the guy on their birth certificate. My 23andMe report showed that I was related to 1,611 of their customers who chose to share their information! However, no one was closer than 4th cousin, and all had less than 1% DNA shared with me, slightly less than eight degrees of separation. This is a relief. I do not need any more first or second cousins, thank you.
Moving on to ancestry, Rick found that he was 94.2% Eastern European or "Broadly" European, with a smattering of Northwestern European, as to be expected for someone who is 100% Lithuanian. No surprises there.
My ethnic ancestry reports confirmed that I was 99.7% European, but instead of 100% Eastern European or "Broadly" European, I was only 84.3! The remainder, of my DNA, 13.2%, was from Southern European, primarily from the Balkans area, with a bit of Sardinia and "General Southern European" thrown in. That means I was not 100% Polish, but I was about one-eighth "something else."
Wow, that's a surprise. One of my four grandparents was only half Polish! But which one? And from what side of the family? And what was his or her other half? Who was the unknown great grandparent, the mysterious stranger in the family?
I asked around in my family.
As it turns out, the identity of our great-grandparents is clouded in obscurity, due to immigration and loss of Eastern European church and civil records during the war. What I know, though, is that my father's father, Marek, is likely to be illegitimate, while the grandmother on my mother's side is the daughter of an illegitimate mother. At the turn of the last century, this was a good reason on its own for a young Catholic person to migrate and keep mum about his or her roots.
What little data we have is the baptismal birth certificate of my maternal grandmother, which indicated she was the daughter of an illegitimate woman and a Polish father whose parents may have been "Greek". Further confusing the issue was a family tradition on my father's family that my paternal grandfather, known to be illegitimate, had an unknown father who was "Greek."
I put "Greek" in quotation marks because it is hard to imagine that each of these families, both from central Poland, had any occasion to run into someone from Greece. People didn't travel far from their homes in those days, and my grandparents lived about as far from the sea as you could be in Europe. I toyed with the idea of a Jewish wanderer, but 23andMe showed that I did not carry and Ashkenazi Jewish genes. Because of the Balkan genetics, I suspect that the mysterious stranger was a visitor from nearby Romania or Hungary. Perhaps in those days, any swarthy, mysterious, Southern-appearing stranger would be called a "Greek" in Poland.
We will never know who was this mysterious stranger and where he came from. There is no one to ask, as the suspect grandparents, and all of their first generation offspring (my parents, uncles and aunts) are deceased.
But that's not the end of the story. We may yet have a chance at finding out what side of the family carries these non-Polish genes if we use genetics. That is, if a cousin on each side would go ahead and do the 23andMe test, we could see which of them carries this Southern European ancestry. Yet it gets complicated. We would have to eliminate cousins that have parents of other ethnicities, who are half Italian or half German, for example. We would have to limit the study to those who are 100% Polish, sharing one pair of grandparents with me, and the other pair all Polish. And who's to say they don't also have a mysterious "Greek" ancestor in their family also?
I will bring it up at the next family reunion. But until we have the genome sequences for most of the rest of the earth's population, we won't be able to locate any of our presumed long-lost relatives. That is a relief. Our family reunion could become unwieldy with 1,611 more cousins.
Posted by Carol A Westbrook at 12:10 AM | Permalink