First a disclaimer. I'm very new to the whole world of genetic genealogy. I'm not new however, to traditional genealogy, and I do have a pretty good amateur understanding of relative archaeological and anthropological discussions over the past fifty years. The following is not meant as a critique of genetic genealogy, so much as a review, or my experience, of ancestry composition based on autosomal DNA analysis.
Let's start with my paper trail.
I am English by ethnicity, British by nationality, and a subject of Queen Elizabeth II (often now referred to as a UK Citizen).
My paper recorded ancestry consists of the genealogical records of:
- Generation 1 has 1 individual. (100.00%)
- Generation 2 has 2 individuals. (100.00%)
- Generation 3 has 4 individuals. (100.00%)
- Generation 4 has 8 individuals. (100.00%)
- Generation 5 has 16 individuals. (100.00%)
- Generation 6 has 29 individuals. (90.62%)
- Generation 7 has 49 individuals. (76.56%)
- Generation 8 has 35 individuals. (27.34%)
- Generation 9 has 24 individuals. (10.16%)
- Generation 10 has 10 individuals. (2.34%)
- Generation 11 has 4 individuals. (0.39%)
- Total ancestors in generations 2 to 11 is 181. (9.04%)
All 181 ancestors, reaching back to the 1690's, appear to be English born, of English ethnicity, with English surnames. The majority of them (100% on my mother's side, and 81% on my father's side) were East Anglian, with the vast majority of that percentage being born in the county of Norfolk. Religions recorded or indicated were CofE Anglican or non-conformist Christian. No sign of any Catholicism, Islam, or Judaism.
Therefore it would look pretty likely, that I can claim English heritage, wouldn't you agree?
Genetic Genealogy and Ancestry Prediction
There are three aspects or avenues of inquiry, available for genetic genealogy. First of all, the two sex haplogroups; the y-DNA, and the mt-DNA. These two "signals" are referred to as haplogroups.
- The y-DNA. This follows the Y chromosome. It is only carried by men. It is passed along the paternal line, and only by that line, from grandfather, down to father, down to son, until the line is broken. What a lot of people do often misunderstand, is that it does not represent 50% of your ancestry. It does not represent all of your biological father's ancestry. For example, his mother's father, and her brothers, although on your father's side, would most likely carry a different y-DNA haplogroup. It only comes down an uninterrupted strictly paternal line. Even at Generation 7 (g.g.g.g grandparents) above, it would have been carried by one out of my sixty four biological ancestors at that generation. The other thirty one g.g.g.g grandfathers for that generation may have carried different Y haplogroups.
- The mt-DNA. Although a very different type of DNA, this one works as the opposite sex haplogroup. It is a signal that is passed down the strictly maternal line, from grandmother, to mother, to her children. Yes, we men do inherit our mother's mt_DNA, but we can't pass it down. Only our sisters can.
- The au-DNA, better known as Autosomal DNA. Whereas the former two sex haplogroups are handy, because we can measure their mutations, and track their formation and movement across thousands of years, au-DNA really is the stuff that we are made of - all of the SNPs on our chromosomes that personalise us within the human genome. We inherit our au-DNA from all of our recent ancestors. Roughly 50% from our biological mother, and 50% from our biological father. Equally, we could say on average, 25% from each grandparent, or 12.5% from each great grandparent. However, it is messy. At every reproduction (meiosis), it gets messed up by recombination. Not only that, but go back much more than six generations, and it becomes more and more likely that you can lose entire lineages. You can have no surviving trace of any DNA from for example, a particular g.g.g.g.g grandparent.
Autosomal DNA is what makes us individuals, gives us our hereditary traits. It is passed down from many ancestors, via our parents. However, the sex haplogroups are of interest because they can be traced across the globe, and the millennia. As we gain more and more data - both from living populations, and ancient DNA from archaeological finds, so we will be able to track the STR and SNP mutation data more precisely.
However, what about poor old messed up autosomal DNA? It represents our entire biological heritage over many generations. It is what we are. However, making sense of it is less easy, less precise. Genetic genealogists are making progress, but it is far less of a precise science than either of the haplogroups. They use calculators, that measure the segments of DNA cross the chromosomes, looking for patterns that they recognise from a number of known reference populations. From that, these calculators predict an ancestry. Exactly what and when that ancestry refers to, does seem to vary from one calculator to another. There is an argument that the precision can be improved if you also test close known relatives including at least one parent. The results can then be phased. I'm actually waiting for the results for my mother, so that I can see my own au-DNA ancestry results phased and corrected.
So lets have a bit of fun, and see what some of the calculators suggest for my autosomal DNA, at least before any phasing with my mother's DNA. What do they make of my 100% English paper ancestry?
23andMe.com Ancestry Composition Standard Mode
83% NW European
17% Broadly (unassigned) European
I think that's pretty cool. As I'm getting to know au-DNA predictions, so as I'm learning to appreciate it when they get the right continent, and the right corner of that continent. That is more than they could do a decade or two ago. The prediction is correct, I am a NW European. I'm not a West African, a South Asian, or a East Siberian.
23andMe.com Ancestry Composition Speculative Mode
94% NW European
3% S European
3% Broadly (unassigned) European.
Whoa, where did that South European come from? It could just be a stray incorrectly identified signal, or it could be telling me that one of my ancestors, maybe around Generation 6, were from down south! Lets break down the prediction further. First, the NW European:
32% British & Irish
27% French & German
But surely I should be 100% British & Irish? Not only 32%. I have my own ideas about this. I think that although 23andMe claims that Ancestry Composition only represents the ancestry of the past 300 to 500 years (the so-called migration period, as sold to USA customers), that it gets confused by earlier migrations across their reference populations, including those during the early medieval period, and perhaps even some of those during late prehistory. I've noticed that across Ireland and Britain, the further to the east, the more diluted the 23andMe British & Irish assignment. People of solid Irish ancestry get between 85% and 98% British & Irish. My East Anglian results, mixed between British & Irish, French & German, and Scandinavian, are actually rather more like those received by Dutch customers of 23andMe.
As for that Southern European prediction, how does that break down?
2.4% Broadly (unassigned) South European.
Which if taken seriously, might suggest that I have an unknown Spanish or Portuguese ancestor around Generation 6. If I did take it seriously that is. I wonder what my mother's test will reveal?
DNA.Land.com Ancestry Composition
This is a third party site, that you can upload your 23andMe V4 raw data to, and see what their calculators predict for your ancestry. It has recently had it's ancestry composition revised. What did that make of my 100% English au-DNA?
West Eurasian 100%.
I like that designation, the amateur anthropologist in me prefers that broad designation over "European". Broken down:
77% North/Central European
19% South European
What? Why not 100% North/Central European? Finnish? Did some early medieval Scandinavian settlers of East Anglia bring it? Or is it a false signal? Misidentified au-DNA?
That darned South European kicked in again. I'm here looking at a biological cuckoo NPE (non-parental event) at around Generation 5 or even more recent! Did a great grandmother secretly have a South European lover? But this South European breaks down further:
Oh my goodness, whereas 23andMe speculative mode suggested SW Europe - this one suggests SE Europe! Do I have a secret Albanian great grandfather? Or is it all nonsense?
This is a cracking new third party DNA analyser. It is based in China, and it's predictors appear to calculate mainly for a Chinese market. It not only predicts your ancestry composition, but also your two sex haplogroups, and lots of traits and health predictions to compliment those of 23andMe. It even tries to predict your genetic disposition to sexuality!
It will allow you to send your 23andMe V4 raw data direct to it's own calculators. However, at the moment the website is almost entirely in Chinese (Mandarin?). There are two options. 1) At the bottom of the webpages is a hyperlink to English, which gives, in English, a basic ancestry composition, and your haplogroups. It does not include English versions of the health and trait results. 2) use an online translator, such as the one built into the Google Chrome browser. It actually serves pretty well.
On sex haplogroups they give my Y-DNA as
L1. Not bad, but they didn't make it to L1b or L-M317.
H6a1a8. Very good. Better than 23andMe's H6a1, and the same as the mthap program.
But this is about au-DNA, how did they do, what did they make of my 100% English ancestry?
Now, that sounds pretty awful, but on closer inspection, I'm impressed. No South European great grandfather. Okay, so most of my DNA has been placed on the wrong side of the Channel. However, I know that French and English DNA is actually very close. Recent surveys even suggest that the English have inherited a lot of common ancestry with the French during unknown migration late in prehistory. So again - they very much got the right corner of the right Continent. Well done WeGene.
GEDmatch.com Eurogenes K13
GEDmatch is a website that you can upload raw data not only from 23andMe, but from a range of testers, and from V3 chips as well as V4. It hosts a number of tools and predictors - some Open Source. Some of these predictors are for Admixture or ancestry composition. They measure your ancestry in terms of distance from known reference populations. The lower the number, the closer you are to their reference. They use calculators known as oracles to predict ancestry, including mixed ancestry or admixture.
The oracles on the Eurogenes K13 and K15 calculator models have a good reputation at working with West Eurasian ancestry. So how does K13 first, score my 100% English ancestry?
On Single Population Sharing, it rates my DNA against the closest references. In order of closest to not so close, the top five are:
3 Norwegian + Portuguese + Southeast_English + Southeast_English @ 2.216714
4 Danish + Portuguese + Southeast_English + Southeast_English @ 2.225334
5 Portuguese + Southeast_English + Southeast_English + Swedish @ 2.230991
GEDmatch.com Eurogenes EU test V2 K15
3 North_Dutch + Southwest_English + Spanish_Galicia + West_Scottish @ 1.282744
4 Southeast_English + Southwest_English + Spanish_Castilla_Y_Leon + West_Norwegian @ 1.295819
5 North_Dutch + North_Dutch + Southwest_English + Spanish_Castilla_Y_Leon @ 1.304939
- Don't expect DNA Ancestry tests to pin point an actual country of ancestry. They're not no where near that good yet. The populations of West Eurasia, and elsewhere, are actually all mixed up, or share a lot of recent admixture. In addition, many European nation-states are quite recent inventions. I've seen the borders of Europe change in my short lifetime.
- Don't expect precision. If for example, you are an American, and a 23andMe AC test suggests only 32% British & Irish, then you could actually have 100% English ancestry over the past 300 years! We're so mixed up, that these tests are struggling to part and identify us by nationality.
- If you are willing to share your raw data (there are privacy issues), then have fun trying out all of these third party calculators. It's a lot of fun as you can see. They rarely agree. There are other tools on GEDmatch for example, where you can compare DNA along with .gedcom genealogical files with other users - and look for shared segments on the chromosomes. You can also compare your DNA to that of ancient populations.
- Treat au-DNA differently to haplogroup results. au-DNA is very interesting, and represents so much of our ancestry, if we could just sort some of the mess out. You can partially do this by phasing your results with those of close relatives. It is worthwhile phasing with at least one biological parent, if you can. However, haplogroup results, provide by their mutations incredible stories over much longer periods - thousands of years. A different kind of genealogy. As we gather more data, and reference it also to ancient-DNA, so it will tell us more and more about two lines of descent. Perhaps even into historical times.