Autosomal DNA
There are several types of DNA but this is the DNA that gets the most publicity – think TV commercials for Ancestry.com and 23andMe.com. You provide a sample of your saliva, pay some money, and wait for 6 to 8 weeks, and then you find out where your ancestors came from.
Yes, the results from those two companies (and a few other companies as well) will tell you if you should be wearing a kilt or lederhosen or kimono at your family reunions, but they can also provide much more information to those who are trying to figure out their families genealogy.
Autosomal chromosomes reside in the center (nucleus) of every cell in our body. DNA is made up of strands of chromosomes. Each strand is a pair of chromosomes, one you get from your mother and one from your father. There are 23 of these strands, 22 of them are related to specific traits, and the last strand is the one that determines your sex. If you are a male, you have an X chromosome and a Y chromosome if you are a female, you have two X chromosomes.
Chromosomes vary in length and are measured by the number of pairs of proteins in each one. They are numbered 1 – 23, beginning with the longest. There are roughly 3.2 billion pairs of proteins spread out over these 23 chromosomes in each person. Certain DNA companies study the relationship of these pairs of proteins and can predict specific characteristics such as hair color, eye color, muscle type, and many more.
Further, each strand is made up of sections. By examining these sections and comparing them to others, we can determine relationships between people. By using DNA samples taken from people around the world and comparing your DNA sample with those from other areas of the world, the computers can determine where your ancestors came from.
The inheritance pattern of autosomal DNA follows a precise pattern – you get half of your DNA from your mother and half from your father. Studies have shown that this inheritance pattern is also reliable back through your 3rd great-grandparents (great great great grandparents). So you get exactly half your autosomal DNA from your mother and half from your father. Breaking that down further, you get a quarter of your autosomal DNA from your mother’s father, a quarter from your mother’s mother, a quarter from your father’s father and a quarter from your father’s mother. This DNA inheritance can be reliably analyzed back 6 generations to your 3rd great-grandparents. Most people would have 32 3rd great-grandparents. Therefore, by studying these chromosomes, ancestral relationships can be determined.
Many genetic genealogists maintain that the reliability of autosomal DNA, when used to determine ancestry, is only reliable going back 5 to 7 generations. Beyond that, you should study other DNA such as the Y chromosome or the mtDNA chromosome which can be analyzed with reliability back thousands of years.
Another interesting fact to consider is that while autosomal DNA testing can be reliable going back around 6 generations if someone has had a stem cell transplant, DNA analysis will detect and be affected by the DNA of the stem cell donor.
Testing Companies
Ancestry.com has the largest customer base both in the number of family trees and the number of people who have had their DNA tested. According to one source, the number of people who have had their DNA tested by a consumer DNA testing company doubled in 2017. Ancestry led the group with 10 million customers.
In 2007, 23andMe became the first company to offer consumer’s saliva-based DNA testing. Additionally, they were the first commercial company to use autosomal DNA for ancestry testing. 1
As of 2017, 23andMe reports that they have tested over 5 million customers.
Although the company was founded in 1999 as a DNA research organization, they did not begin consumer DNA testing until around 2012. They have a partnership with the National Geographic Genographic Project. Being privately held, they do not release their customer numbers, but it is estimated that they have tested over 2 million people.
Others
Other testing companies include MyHeritage, LivingDNA, and WeGene to name a few.
Who I Am (according to DNA tests)
Each testing company has their proprietary testing method. They all gather genetic samples from volunteer subjects from around the world. They all develop sophisticated algorithms to analyze the submitted DNA. They all invest heavily in powerful computers. Even with these computers, it takes an average of four to six weeks to study and map out the millions of DNA base pairs for each customer and get the results posted.
It is also important to note that all companies update their results as their algorithms are refined, their regions expanded as well as the number of reference subjects are added to their DNA baselines.
So what have I learned from each of the companies I have tested with?
Ancestry.com
As of May 2018, Ancestry.com tests for a total of 166 regions from around the world and uses DNA samples provided from 2995 people.
Ethnicity Estimate
| Region | Percentage |
| Great Britain | 49% |
| Ireland / Scotland / Wales | 37% |
| Europe West | 8% |
| Low Confidence Regions | |
| Europe South | 2% |
| Scandinavia | 1% |
| Iberian Peninsula | 1% |
| Middle East | 1% |
| Nigeria | <1% |
Although Ancestry makes a distinction between the Great Britain region and the Ireland / Scotland / Wales region, the Great Britain region includes England, Scotland, and Wales. The difference has to do with the different origins of people from those regions. For a practical matter, I say, that according to Ancestry DNA, I am 86% from England, Scotland, Ireland, and Wales – but I like to think I am more Scottish at heart.
23andMe.com
23andMe gathers DNA samples from over 10,000 individuals in 151 population groups from around the world.
| Region | Percentage |
| British & Irish (United Kingdom) | 52.9% |
| French & German | 7.8% |
| Scandinavian / Iceland | 3.4% |
| Italian | 2.7% |
| Broadly Northwestern European | 31.1% |
| Broadly Southern European | 0.5% |
| Broadly European | 0.9% |
| Sub-Saharan African | 0.8% |
| West African | 0.7% |
| Broadly Sub-Saharan African | 0.1% |
Their results indicate 52.9%, British & Irish. Looking closer at their data, it shows that their analysis has a confidence rating of 5 out of 5 that I am from the United Kingdom but a 2 out of 5 confidence that I am from Ireland. Although it says I am 7.8% French and German, the computer has not been able to narrow it down to a particular region (for example, Austria, Belgium, France, Germany, Luxembourg, Netherlands or Switzerland). As more people are tested, and more reference samples are added to the study, this may change. I did find it interesting that the Scandinavian / Iceland listing of 3.4% shows a confidence of 2 out of 5 for Iceland and nothing definite for Denmark, Norway or Sweden. Maybe a trip to Iceland might be in order!
FamilyTreeDNA.com
FTDNA analyzes DNA samples from 24 regions. I have not found out how many individual DNA samples are used for reference.
| Region | Percentage |
| British Isles | 89% |
| Southeast Europe | 9% |
| Iberia | <1% |
| East Central Africa | <1% |
| West Africa | <2% |
No surprise here – test results still indicate the British Isles although it would be nice to have them break it down further since they only reference 24 regions instead of 166 like Ancestry or 151 like 23andMe, that information is not available, yet.
FTDNA is not nearly as active in the DNA region analysis. What does set them apart from the others is their analysis of other DNA chromosomes, the Y chromosome, and the mtDNA chromosome. They are leaders in this area.