Autosomal DNA

Autosomal DNA testing is the latest breakthrough in genetics and can be a useful tool in genealogy. In 2009, 23and Me launched their test dubbed “Relative Finder”. Following on their heals in 2010, Family Tree DNA launched “Family Finder” and in 2012, Ancestry launched “AncestryDNA” which was at the time more affordable solution. Since then prices have dropped and all three offer the test for $99.
Last Fall, Roger Burbank told me about taking the test. He had used Ancestry and because I was already a member I opted to take the test with them. For those interested in taking the test, I’ve included a link to a comparison chart at the end of this article.
Unlike the yDNA test, the Autosomal DNA test isn’t conducted on the sex chromosome. Instead, it examines the other 22 chromosomes for strands of DNA that match other testers. Since the test doesn’t use the sex chromosome, both men and women are able to take it. Using mathematical algorithms, the testing company is able to determine with fairly high accuracy that relationships exist between people, but only if they have a relatively recent common ancestor.
Autosomal DNA can be understood like a pack of playing cards. Every time a baby is made the cards are shuffled. One half of “the deck” comes from each parent. Our parents received half of their DNA from their parent and so on. It happens in a process called recombination, and it is random. That’s why siblings don’t look exactly alike. While it is random, long blocks of DNA tend to stick together. Often people who are closely related will share these long blocks. The longer the shared block, the closer the relation.
How can this be helpful to genealogy? All of us have 16 sets or thirty two 3rd great grandparents so chances are we all have hundreds of cousins that share our DNA that we know nothing about. If we are able to find these cousins and collaborate, we might be able to pool information and get a better understanding of a common ancestor. It may, for some, help to break down walls that paper research hasn’t been able to solve. For most, it will help confirm paper research.
To have the best chance at getting good results, a tester needs to have researched multiple sides of their family going back as far as possible. For example, a match might show a 95% probability match with another tester and indicate a 4th to 6th cousin. However the test can’t tell you how you are related. If your family tree isn’t filled out it would be difficult to determine relation and that is if you are lucky enough to match someone with a extensive tree. If you haven’t already done a lot of research on multiple branches you might not get much out of the test except the ethnicity estimate, which we will talk about later in the article.
You also may need to spend a lot of time examining your matches. In some cases, I had a good idea where the match was, but I had to eliminate other possibilities to feel confident. Sometimes that isn’t possible. Often when I got stuck or found myself spending too much time trying to fit the pieces together, I simply had to move on to the next match. There were pages upon pages of potential matches. In my first few weeks with the results, I worked on it hours a day. If you enjoy genealogy, it’s almost an endless source of work. I receive new matches weekly and have contacted a few cousins although none very close. As they develop new algorithms they will run my DNA through them at no extra cost.
Some of matches were high probability but I don’t suspect I’ll ever figure out how we are related, if in fact we are. Others were easy. We shared a common ancestor and Ancestry pointed that out. Of course they can only point that out if they find the common ancestor in both of our family trees. Often the ancestor wasn’t on a side of the family I was researching, but it was still interesting to see what families I inherited DNA from, and it also confirmed my paper research.
There are big challenges. I ran into matches without trees, matches with very few people in their trees, and matches with locked trees where I had to request access. Ancestry allowed me to contact these users and most granted access. Some didn’t know how to grant me access, and I never heard back from a couple. As I continue to receive new results, I’m able to filter out the old results so I don’t have to wade through matches I’ve already reviewed.
It can be fairly hairy. For example if I had a match with someone who descended from the Virginia McCutcheons I’d have to eliminate the possibility that we weren’t related in another way. Since my grandmother was a Campbell she and I could share DNA with Grisal Campbell who married James McCutcheon of Augusta County, Virginia. If I wasn’t able to eliminate that possibility with research, I might have to get a cousin tested.
One feature Ancestry recently added is the ability to search results by surname or by location. Of course when two people match a surname it doesn’t mean they are related. All of us have 128 5th great grandparents so chances are 2 unrelated people who compare family trees that far back are going to have some surname in common. It’s important to stress that Ancestry doesn’t know where the match is, and is only making very good guesses that there is a relationship. Some of these guesses are high probability and some aren’t. It’s up to the tester to determine if there is a relation and where it might be.
One thing that I don’t like is that when you reviewed another user and see the shared surname list, it doesn’t take into account different spellings of a last name. If I were to match someone on the Kennamer name, and they spelled it Kennemur, it wouldn’t show up in our shared surname list. Still I can scroll through the rest of their names that appear under the shared surnames box, and I can also search the surname Kennamer and ask for variants. Ancestry also has a tab that will let you see shared birth locations which can be helpful.
Ancestry also gives you a “Ethnicity Estimate”. For me it showed Great Britain 42%, Scandinavia 35%, Iberian Peninsula 11%,Europe East 7%,Trace Regions 4%. There is also a map showing what areas my DNA came from and it had historical and anthropological information about each region. They do this by comparing segments of my DNA to people in these regions. As more testing is done they are able to narrow it down further. My DNA origins weren’t a particular shock to me but I understand some people who aren’t necessarily interested in genealogy are taking the test solely due to interest in their ethnic heritage.
Some people get answers that they weren’t expecting and in many cases don’t believe. Each of the testing companies have their own method of determining ethnicity so it could vary some from company to company so a tester could verify their ethnicity by taking the test with another company.
One thing I found interesting was that since recombination is random, siblings can get different results. I might inherit DNA from my 3rd great grandmother, but my siblings may not have inherited any of her DNA. That’s where the card shuffling analogy falls apart because some DNA eventually gets left out. That’s why my test could show Eastern Europe and my sibling might not have had any Eastern Europe DNA.
Another interesting thing I discovered while researching this article was that Ancestry allows you to download your raw DNA. It’s simply a large text file. There are sites you can upload your DNA to that will allow you to compare results with people who took the test from other companies like 23andMe. I uploaded mine to gedmatch.com. Since I discovered this just recently, I won’t have any results back for several weeks so I can’t really review that process but I can see there are a bunch of 3rd party DNA tools that will allow users to expand on what Ancestry has done and it’s all free.
While this type of testing is relatively new, it has improved in just the brief time I’ve taken it, and I can see plenty of room for new discoveries as more and more people participate. The following link might be helpful for those trying to determine which company to use.

http://www.isogg.org/wiki/Autosomal_DNA_testing_comparison_chart