DNA Testing – Part 1: Autosomal DNA

This starts a four part introduction to the subject of DNA testing. I’m not an expert. Like many of you, I am still learning this stuff. Some of it is pretty easy to understand, but once you get down into the weeds it can get pretty complicated. I highly recommend exploring and bookmarking the following blogs that cover Genetic Genealogy:

Roberta Estes – DNAeXplained – Genetic Genealogy Genealogy – Roberta is Administrator of the Muncey Project at Family Tree DNA

Kitty Cooper – Kitty Cooper’s Blog: Musings on Genealogy, Genetics and Gardening

One thing is certain. Genetic Genealogy is the future. It can help answer family mysteries and offer new paths when traditional research comes to a dead end. If you or other family members have not been tested — well, you will eventually want to be tested. Trust me. It’s important.

The Basics

If you have turned on a television in the past few years, you will have seen advertising for Ancestry.com and 23AndMe – two services that offer DNA testing used in genealogy research. Your may not have seen advertising about Family Tree DNA (FTDNA), but we will talk about it later.  I haven’t used 23AndMe, but I’ve been a long time user of Ancestry – but I didn’t take advantage of DNA testing until a few years ago. Once I took the test and saw how important it can be to family research, I immediately tested my father (now deceased), my mother, and my sister. I’ll get my brother to test eventually.

The tests done by Ancestry, Family Tree DNA and 23AndMe test autosomal DNA (atDNA) – the DNA that is passed down to you from both your mother and your father. The International Society of Genetic Genealogy (ISOGG) has an excellent comparison chart of the differences between the autosomal DNA testers that you can review here.

Autosomal DNA is the 22 chromosomes you inherit that don’t contribute to gender. (We’ll look at the gender-specific y-DNA chromome in the future.) You inherit approximately fifty-percent of your DNA from each parent. Your father inherited about fifty percent each from his father and mother, and your mother inherited about fifty percent each from her father and mother. That means  that about twenty-five percent of your DNA is inherited from each of your grandparents, and about 12.5 percent from your great-grandparents. You can extend that out to get about 6.25 percent from each of your great-great-grandparents, or a little over three percent from your great-great-great-granparents.

You will probably have traces of autosomal DNA from your 5G grandparents, but that is getting to the point that it is hard to identify. That is the reason I rushed to get my aging father and mother tested. Using their DNA results pushed out the possibilities of DNA matches another generation. I wish these tests had been available when my grandparents and great-grandparents were alive. I’ll make this recommendation… If your grand-parents or great-grandparents are living, run (don’t walk) to get them tested NOW.  Once they pass, that opportunity is gone forever!

A really important fact is that the autosomal DNA I inherited from my parents is random. I will get about fifty percent from each parent, but my sister may inherit a completely different fifty-percent from each parent– and my brother may inherit a completely different fifty-percent from me and my sister. Now you understand why I wanted my siblings tested!

The Tests

Depending on the service you use, you will either provide a DNA sample using a “spit test” in which you provide a vial of saliva to be returned to the company (Ancestry and 23AndMe) or a “swab test” (FTDNA) in which you swab your cheek with a special collector (special Q-tip). Neither is hard. Both require you to have abstained from eating and drinking for a certain period of time. After you collect your DNA sample, you will ship it back to the testing company in the mailer they provided. Then you wait for the results…. and wait, and wait and wait.

(Although 23AndMe provides an advanced health test for an additional fee, this test is not all-inclusive. A list of the health reports they can provide is available from their web site.)

The basic autosomal DNA (atDNA) tests provided by FTDNA, Ancestry and 23AndMe are focused on genealogical research, tracing ancestors and establishing family relationships. They are not designed to predict cancer, predisposition to Alzheimer’s, or tendency to insanity. Your individual results are not going to affect your insurance and will not be used by government agencies to determine if you are descended from aliens. However, collective results may be provided from the testing services to be used in research or commercial projects. Some people worry about this. Other’s don’t. I don’t worry about it because even if my results are provide to a third party, my name isn’t provided — only the results. Read the disclaimers carefully.

The Results – Ethnicity, Ancestry and Matches

After waiting an interminable period of time (usually more than a month), you will be notified that your results are in. You will get interesting statistics and graphs showing your ethnicity and where your ancestors came from in a very broad sense.

You should take these results with a grain of salt! These numbers are only estimates and should be viewed as ranges. From Ancestry, my ethnicity shows 57% came from Great Britain, 24% from Ireland, 10% from Scandinavia, and a smattering from other regions.  (My sister shows 51% GB, 31% Ireland and 10% Scandinavian.) FTDNA shows my ethnicity as 58% central and western Europe, 39% from Scandinavia, and 3% percent from the British Isles. These results came from the same sample since I uploaded my sample file to FTDNA that I had taken for Ancestry. So why the huge difference?

I believe it is mostly a matter of timing, and I believe that the analysis of FTDNA digs a little deeper than Ancestry.  For example, based on my y-DNA testing (not included in this analysis), I know that my male “Muncy” ancestors came from Norway/Sweden to England over 1000 years ago. The FTDNA analysis picks up on the Scandinavian ancestors that moved into England, whereas Ancestry picks up their later location as England and Ireland.

However, where the ethnicity results are very helpful is in identifying groups like Native American, Ashkenazi Jewish, African, etc. If you want to find out if your great grandmother was Native American, this test should tell you.  (As an aside, as a child I was told by my ancient elders that I was part Native American. I’ve since learned that this is frequently rumored in family histories, but I grew up wondering if I should take the cowboy or Indian side when playing. Well, subsequent traditional research followed up by confirmation of DNA shows that I have no discernable Native America blood AT ALL. Zilch. Nada. )

After the results are complete, the testing company begins the process of identifying matches that have also tested or uploaded their results to that service. Before long, you may have hundreds of matches showing you a range of  1-2nd cousins, 3-4th cousins, 5-6th cousins, etc. Over times matches can add of up. I currently have about 17,000 matches on Ancestry, of which about 1,000 are 4th cousins or closer. That number ceases to be useful it itself, but when multiple-matches are shown to be related to each other, it becomes extremely helpful.  Shared matches can begin to yield additional information you did not have before, and validate otherwise questionable relationships.

If other members of your family also test, you can administer their test results. For example, I administer the DNA results on Ancestry for my deceased father. He has about 700 matches at the level of 4th cousin and closer, and his results will extend back farther and won’t be mixed with the DNA results of my mother (for whom I also administer test results.)


I can’t recommend 23AndMe — mostly because I have not used them and am not familiar with the service.  I do know that 23AndMe has had some reporting issues in the past and it attempting to “reset” itself, but I suspect that their current testing is fine. I know that Roberta Estes DNAeXplained blog has covered some of the past issues for 23AndMe, so I refer you back to her for more information.  Both Family Tree DNA and AncestryDNA are good services and tests. I have personally come to prefer FTDNA primarily because of the additional analysis tools they provide, but AncestryDNA is excellent also.

One issue I have with Ancestry is that to communicate with matches you must use their internal messaging system which is not good. Sometimes internal messages are not delivered. Sometimes other users have accidently turned off receipt of messages. My biggest issues, however, is that sometimes people don’t log in to Ancestry for weeks or months at a time and don’t get your message  until long, long after you sent it. (In theory you can be notified of new messages by an email to your email account, but this doesn’t always work.) I have messages to Ancestry matches sent months ago to people who haven’t logged in for more than a year, so it is questionable if I will EVER get a response.  FTDNA provides the email address for all matches so you can communicate via email (my preferred method since I archive all my email) and my response rate is much higher than that of Ancestry.

FTDNA will accept transfers (for a fee) of testing done at Ancestry but not vice versa. If you are currently an Ancestry subscriber, it would probably be best to pay the higher fee (currently $99) and then transfer the results to FTDNA (about $40). If you are not a Ancestry subscriber, or don’t plan to become one, you might be better off using FTDN’s $79 Family Finder test. FTDNA also offers additional tests -y-DNA and mitochondrial DNA) that are not available from the other services, and FTDNA offers superior analysis tools. For those who are interest in following surname projects, the y-DNA test is essential (offered only by FTDNA).


In Part 2 of this series, we will look at y-DNA, the Y chromosome that is passed on only from father to son, and it’s importance in tracking surname ancestry.

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