Welcome back to Tenacious Genealogy! Today, I’m going to focus on the genetic aspect of genealogy. Genetic ancestry adds a new dimension to family history, sometimes enriching our sense of identity and sometimes making us re-evaluate it. But it is an aspect that can’t really be ignored. Because of this, there are a variety of companies (both genealogical and not) that offer DNA tests to consumers. I’m going to talk about Ancestry’s offering – AncestryDNA.
1) AncestryDNA is massive
AncestryDNA, just like the website that it is a part of, is the big fish in the pond of DNA services. It’s been around for several years and according to its website, has over 5 million DNA samples (as of August 2017). EDIT: as of September 2018, they had over 10 million samples.
To put this into context, the next biggest company in the realm of genetic genealogy is 23andMe. 23andMe just surpassed 2 million samples in April of 2017. (Over 5 million in September of 2018) The three other main competitors (Living DNA, FTDNA and MyHeritage) have just started their services, so their databases are still relatively small. (According to DNAGeek, these are the rough estimates for September 2018.)
In regards to genetic genealogy, database size is a decent predictor of how accurate the results will be. Basically, the bigger the database, the more people your sample is tested against and thus, more accurate results. So, in this regard, AncestryDNA’s results are (currently) the most accurate. However…
2) AncestryDNA results are nuanced
So genetics (and genealogy) are usually more nuanced than they seem at first glance. The first thing to know is that DNA is usually measured in a unit called a ‘centimorgan‘. I won’t get into the nitty-gritty of what a centimorgan is, but for the sake of genetic genealogy, it’s the measurement of the distance between genetic markers in autosomal DNA (the DNA that everyone gets from their parents).
Centimorgans is a big part of how services like AncestryDNA can tell how closely related someone is to another person. Generally speaking, the more centimorgans you have in common with someone, the closer you are related to them. A great basic visual chart is located here.
However, if you have multiple common ancestors with a person, you might have more centimorgans in common than the average person with that same relation. For example, if both a person’s grandfather and grandmother had ‘Smith’ ancestry (even if they weren’t direct cousins), their descendants may have more centimorgans in common than normal. You generally see this within groups that practice a lot of endogamy, but that’s a whole other blog post to write about.
Similarly, you only get up to a certain percent of a parent’s DNA. Usually it’s about 50% (I share 50% of my mother’s DNA and 49.9% of my father’s according to AncestryDNA), so with each generation, the chance that certain pieces of DNA got passed down to you goes down due to something called ‘recombination‘ (This is a really good blog post on the subject).
For example: my great-grandmother was full-blooded Swedish/Scandinavian. Which means I should be about 12.5% Scandinavian (given that I’m not getting that ancestry from any other lines). But according to AncestryDNA, I’m 6%. And that’s okay. All it means is that either my grandmother or father were more like their fathers, genetically. Or both. Or even that I’m more like my mother than my father (which technically is true).
Also… because of recombination, even if you and your siblings all get 50% of Mom and 50% of Dad, that doesn’t mean you all will get the SAME 50% from each parent. It’s not uncommon for siblings (even fraternal twins, triplets, or other multiples) to have a range of ancestry percentages. Ancestry has a good informational page about this concept as well.
Lastly, results from AncestryDNA are always changing. But this is a good thing. They are changing because the database that Ancestry is using is getting larger (and more diverse). As databases such as AncestryDNA’s get larger, there are more DNA samples to match against yours.
An example of this that I’ve experienced is the percentage of Irish (technically Celtic/Gaelic) DNA that AncestryDNA says I have has shot up since I initially took the test. Because I only have one known Scottish (which is Ancestry includes in Irish DNA) line, I expected maybe 10-12% Irish DNA. And originally there was less than that – about 7-8%. Now my results show me as have 19% ‘Irish’ DNA. (Which probably explains my fair complexion and inability to tan…)
Based on the growth of AncestryDNA, I can only assume that more people with ‘Irish’ DNA (really Celtic/Gaelic) have taken the test since I did and so AncestryDNA can more solidly tell me that I am a good part Irish/Welsh/Scottish.
3) AncestryDNA can (maybe) tell you whether you have Native American/First Nations ancestry, but not which tribe
Some people take the AncestryDNA test in order to find out whether that story of having a Cherokee princess as a great-grandmother is true. However, AncestryDNA isn’t going to tell you if you are part Cherokee (or Ute, Iroquois, Apache, Sioux, etc, for that matter.)
While AncestryDNA can tell you whether you have Native American/First Nations ancestry (within reason – check out this article that goes more in-depth into the subject of Native American ancestry and genetics), it is virtually impossible for AncestryDNA to differentiate one tribe from another solely on genetics.
This is primarily because most of the different tribes (at least in North America) are part of the same haplogroup, so the majority of their genetic markers are going to be similar to each other. As well, anecdotally, there have been less Native American/First Nations people who have taken DNA tests (especially the AncestryDNA test), so that subgroup is less represented in the overall database.
4) AncestryDNA can connect you with distant family members
Genetic Communities – These are groups of people who are connected to each other through DNA because of having common ancestors in a specific region. This is a relatively new aspect of AncestryDNA (still in beta, technically) and seems to heavily rely on how many people/descendants from a particular area have taken the AncestryDNA test. According to Ancestry, they have about 300 genetic communities around the world and will be introducing more in future months.
Currently, I have four genetic communities right now – two from French settlers in Quebec and the surrounding areas, one from Sweden, and one from Mormon pioneers in the intermountain west. However, family members that I’ve talked to (and who have ancestry in Asia) have noted that genetic communities haven’t popped up for them yet. This could possibly be because there aren’t enough samples yet from the part of Asia that they are from.
DNA Matches – The main ‘connector’ area in AncestryDNA. It’s here that you can see other people who share sections of DNA with you. Ancestry DNA even organizes them from closest relation to distant relation.
The big thing to understand about DNA Matches is that however close you are to another person is an estimation. The estimation is more accurate for closer relations and then gets more fluid the farther removed you are from a person. For example, you and your parent (or child) have 1 degree of separation. You and a sibling have 2 degrees of separation. You and a cousin have 4 degrees of separation. With all of these, Ancestry will tell you that there is a very high chance that the two of you are closely related.
Which is why this is about as far out as AncestryDNA will organize your relations. After that, you have Distant Cousins, which AncestryDNA notes as being distant enough that while you share DNA with them, it isn’t enough to be totally certain.
DNA Circles – These are groups of people that Ancestry can tell are related to you through a common relative. On its website, Ancestry states ‘A DNA Circle is a group of individuals who all have the same ancestor in their family trees and where each member shares DNA with at least one other individual in the circle.‘ While it is an aspect of AncestryDNA that is still in beta, it is an interesting item to play around with. If you click on the question mark in the upper right-hand corner of the ‘DNA Circles’ block, it will pull up a bunch of questions and answers about DNA Circles.
5) AncestryDNA can uncover family secrets
And now the uncomfortable side of AncestryDNA…
For all of the cool and wonderful information you can find out with it, there is always the surprises and stories that are hinted at by DNA.
Sometimes these surprises are benign (like my mother finding out she has DNA that was common to people in Great Britain – ‘But I don’t have any English ancestors!‘) Other times, it isn’t so benign (like when a family finds out they have a sibling or half-sibling they never knew about). And then there are the times when people think they have a certain heritage and come to find out that they don’t, leaving them to try and re-evaluate who they are.
Unfortunately, as many people who’ve taken DNA tests such as AncestryDNA have found out, science doesn’t give a **** about feelings or who we ‘identify’ as. Or family secrets. Or social mores. More often than not, we share DNA with groups that we may not necessarily like or be fond of. People may find out that the culture or ethnicity that they thought they were, really isn’t part of their genetics. This is a risk taken by anyone who takes part in DNA testing. While DNA is nuanced (and may not tell the full story of our ancestry), the facts it gives do not lie.
That said, taking a DNA test (especially through AncestryDNA) isn’t a bad thing. I am glad that I took mine, and it certainly made me want to explore my ancestry and heritage a lot more. Given the large (and ever-growing) database that backs up AncestryDNA results, I would highly recommend it. Right now, pretty much all of the DNA services are offering sales for the holidays, so if you are interested in purchasing an AncestryDNA kit, now is the time to do it. You can do this through their website.
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