Genetic Genealogy:

is it worth it?

This is an important question, and one which I think the answer is going to be seen as not very helpful. In short: none of the current providers of DNA testing are worth it.

image: screen capture of 23andMe — DNA Genetic Testing & Analysis page. Green cone is me

No matter which of the companies you give your sample to, from the very best to the very worst you will see a picture like the one above, typically generated using some form of PCA. This is a process by which millions of dimensions (such as found in variations of the genetic composition of individuals) can be broken down and transformed such that the first few dimensions contain most of the variation in individual character. This doesn’t “reduce” the number of dimensions, per se, just reorders them in a way that maximizes distance on a graph of one or two dimensions.

So my first critique of why you shouldn’t bother with genetic analysis is that there’s not a lot it will tell you that you don’t know from looking in the mirror: white people top left, asians top right, africans bottom left. Literally, there’s no way I can plot that chart without it having some racist connotation, because of one of the flaws of these services: if you try to be everything to everybody…you’ll be nothing to anybody.

image: screen capture of Genetic Ethnicity Details at AncestryDNA

At best, each of the sites is trying to make an inferral about where specific pieces of your DNA come from some earlier point in time.

Let’s talk about how I seem to have 36% Scandinavian and 2% Finnish DNA.

My father’s father was first generation American, born in Ruthenian Austria. 27% Eastern Europe explained. My mother’s mother was born here, but her mother was 1st generation good Horan from Tralee, Ireland. Grandma’s father was from Walldorf, Germany. My mom’s dad’s family descend from a well documented German family line, the Feistels, who married into Civil War era Porters from NY/Ohio, who were probably SAR/DAR, and then to the Zehs, German farmers from Long Island. So a good %age, say 37%, should be Western Europe or British Isles, and another dose, 12%, Ireland. My father’s mother was born here, but her parents were fairly German, Lohrmann/Hemerlich. another 25% or so Western Europe.

image: screen capture of Family Tree DNA — My Origins

OK. So if you look at my distant (presumed IBD) relatives, and assume 75% western Europe and British isles, 25% Eastern Europe, this third graphic is a bit more… truthy. My Scandinavian descent is probably coming from common Celtic/Gothic origins, and my membership in J2b1a mitochondrial haplogroup probably dates in some distant way from the North, since I have a mutation that is associated with warmer body temperatures. As you can see below, my maternal line contains five additional mutations beyond J2b1a unique to me (and probably also mom).

image from Post by Matt Harbowy on The Exome Experience

Which brings me to a second important point: ask yourself- what are you looking to get out of genetic genealogy? In the chart above, through full mitochondrial sequencing, I can trace my lineage back to Clan Jasmine of Eve, of the modern mythology from Bryan Sykes. Unlike the ancestral analysis in the previous three graphs, mitochondrial sequence is short enough that each mutation can be called out and labeled individually and is guaranteed* (some limitations apply, check store for details) to come from your maternal line. It’s absolutely true, and absolutely meaningless, because each step backward is perhaps thousands of years. Yes, we all descended from a line of women who all descended from a single woman’s mitochondria. We don’t know what she looked like, or if she was more ape than man.

Jasmine of Eve (Artist’s rendering*)

My great-great-great grandmother’s name was Johanna, and so in deference to J, let’s call that the Johanna line. Services like Family Tree DNA and other “first generation” providers used forensic style markers: Y-STR and mt-DNA HVR SNPs. They only used sex-determining DNA, not autosomal DNA, and not X-chromosomes. These companies, and the oversized personalities that promoted them, made a lot of blanket, simplistic statements, like who were Kohens, or who were Nialls, or Khans. For many, it was like past life regression- with a soupçon of science thrown in. Most companies who provide results call out Jasmine (NB: not Johanna), dot dot dot, a bunch of tenth cousins and you.

Having had my sequenced haplogroup “Johanna” published and publicly available for about 5 years now, I am utterly bowled over at the resulting… silence. I’ve managed to connect to about 5 people who I can say with any scientific certainty are distant relatives I didn’t know before DNA testing. None who give me any insights into the gaps in my family tree, and the only one who might confirm my paper trail genealogy hasn’t returned my match request on 23andme. Am I a special case? If you’re a Kohen, or a Jefferson, or (disproven in 2007) a Tsar’s daughter, there’s probably some merit in one form of testing, either first-generation STR/SNP or second gen gene-chip tests like those I have listed above. But most people will just get a chinese-fortune level of truth, and beware any “reading” that says you’re descended from Nefertiri; it’s probably more like her 4th cousin’s daughter’s roommate, good old third spear-catcher from the left. I’m not scoffing at the desire to find family, particularly if adopted: I’m just saying, these things are always “be careful what you wish for”. Humans are, if anything, non-monogamous.

Which brings me to what you might want to try if you’ve got some serious scratch (or exhibitionist streak) and want to try for full genome sequencing. It’s not going to tell you much more than the gene chip, but if you’re seriously investigating the whos and wheres of certain genetic traits, you can certainly do a lot worse than the free full genome sequencing of the Personal Genome Project. I’ve just gotten my results back and they represent calls on 96% of the currently “callable” sequence (89.4% of all my human DNA, since even today 10% of the genome is still “dark matter”, mostly long repeats and stutters). Ping me again in a couple years when I finish looking through the 1 1/2 gigabyte file that shows all the data.

Which is my third and final point: ancestry research has always been a mix of part legend, part half-truth (pardon the Yogi Berraism), part truth-you-allow-yourself-to-hear. The individual companies (as well as I) can bloviate at length about the level of scientific accuracy, the “coverage”, the meaning of any one snp, but unless we have lots more ancient preserved DNA sequenced, there’s little hope to uncovering real hard facts about the descent of man. And, unless you’re one of the lucky people to have a “trailblazer” loon like myself in your family, you’re going to see a lot of data, very little of it meaningful or relevant.

Take, for example, my Ashkenazi wife. Her family tree happens to be a mobius strip, as does many Ashkenazim, because (not so) many generations ago, pairs of cousins intermarried. As a result, her genotyping looks far more recent than it actually is, since it is subject to less mixture with non- or very distant- cousins. She has huge loops that match with millions of people alive today, whereas the likelihood that you will find direct descendants within 7 generations of me is very slim. Most of my matches exceed 9 generations, and only the Feistel line, mostly in Germany, mostly(all?) who have not been genotyped, has any trace of documentation back to the heady days of the 18th century. If you ask Grandma, she’ll tell you it’s because we’re secretly illegitimate Hohenstaufens of Prussia and if that fact ever gets out, we’ll all be murdered in our beds… um, I wasn’t supposed to tell you that part.

That said, this is a game of luck, of chance, where the odds of winning go up a lot as more people publish un-redacted full genotypes or genomes. That’s a big if: we still don’t know what most of that spaghetti code means, whether it codes for things like good looks or exquisite manners or talent with math, whatever you might hope your genome to say. We don’t actually know how to make people live longer, or live better, or have a better chance at being rich or talented. As far as we can tell, within statistical error genes don’t code for any of that. There are even lots of people who have genes that definitely code for bad things, yet those things never befall them. Those of us who are pioneering genetic mapping are banking on a future society which is less totalitarian, less fascist. We are banking that there’s nothing in our genes that might embarrass our kids, our grandkids, our parents, our cousins. We’re banking that DNA evidence won’t be used against them, or planted falsely. From where I stand, the risk is worth it, and I’ve basically dragged all of my relatives, tested or not, along with me for the ride.

I can’t, though, in good conscience, recommend that anyone do any of that. The likelihood of you discovering some breakthrough, some big scientific or genealogical barrier felled by your drops of spit, is near close to zero. More likely you’ll wind up at some company or on some chat group that will tell you you are the lost prince of oobleckistan and you’re going to spend a lot of time conflicted, unsure of who is telling the truth, and who might be just an internet loudmouth. I would know.

This article originally appeared Apr 26, 2016 on Quora.

matt harbowy, an internet loudmouth, is also a scientist, activist, and data management expert. He is one of the founders of the non-profit Counter Culture Labs working to bring fairness and egalitarian ideals to people interested in learning about science and biotechnology. He is also a top writer on the question and answer site, Quora.