Q: Which company has the best ethnicity estimates?
A: First of all, it is important to note that there are three factors that effect the ethnicity estimates you receive from your testing company, no matter which one you choose. The first two, fancy math and timing, we will save for a later discussion. But the most relevant to your question are the reference populations, or the people your company is comparing you against. These are just regular people living today whose DNA can be used to represent the DNA of a particular area. This is because their four grandparents all lived within 60 miles of each other in your ancestral homeland. The most important thing to keep in mind is that if the testing company you choose doesn’t have a reference population referencing your ancestral population, they won’t be able to tell you that you are from there, even though you really are.
For example, Family Tree DNA does not have an ethnicity category specifically for Irish. So even if you are 100% Irish, you will still not find the term “Irish” in your DNA test results. You will be in the British Isles category. When you see that designation, you might think that this category still fits you, as arguably Ireland is in the British Isles. However, if you apply that same principle to someone living in Poland, the results might not be as clear. Without a good reference population for Poland, a Polish person may find themselves in a Broadly European category. Which does still technically represent them, but is certainly too broad to be interesting or useful.
One answer to your question is, “The best ethnicity estimate will come from the company who has your ancestral population(s) as a reference population.”
Each of the companies provide a complete list of their reference populations so you can check that list to determine which company may be best for your particular mix of heritage.
DNA Companies’ Areas of Speciality
All of the companies are going to be good at providing a basic background for those of western European descent, but some companies also excel in other areas of the world. See the list below for a quick rundown of each company and what areas outside of general western Europe they specialize in. No matter where you choose, be prepared for changes and updates as this is an ongoing area of research.
23andMe: 175 total reference populations. Good for people with eastern European or South or Central American ancestry.
AncestryDNA: 43 reference populations (with hundreds of Migrations). Their specialty is in helping immigrants connect back to a more specific location or homeland using their DNA Migrations tools. These help you determine where your ancestors were in the last 200 years.
Family Tree DNA: 24 reference populations. The most basic offering of all companies, they don’t really offer much more than a basic view of your heritage.
Living DNA: 80 reference populations. Living DNA breaks up the UK into 21 pieces. You can see not only that you are from the UK, but that you have 12% of your heritage from Northumbershire and 6% from Devon.
MyHeritage DNA: 42 reference populations. They are best known for their five Jewish populations, but they also have some other unique populations like Indigenous Amazonian and Inuit.