See Also: Which DNA Test Should I Take?
Many of us are interested in having our DNA tested to learn more about our origins and ancestors. But which one of the several companies offering DNA ancestry testing should I test with? The answer, as in many areas of genealogy, is "it depends." Factors to consider when selecting a DNA testing company include:
The Size of Their DNA Database
DNA testing for ancestral purposes is most useful and accurate when comparing your raw DNA results to as many others as possible. Each company relies on its own proprietary database, which means testing with the company with the largest database provides a greater chance of achieving useful matches.
Will They Allow You to Download/Transfer Your Raw Results?
Because different people test with different companies, most of which maintain their own databases of tested individuals, you will achieve the greatest chance of useful matches by either being tested, or sharing your DNA results, with as many companies as possible. Look for a company that will allow you to download and/or transfer your DNA results to other company's databases. Access to your raw results also allows you to share (if you wish) with public DNA databases and third-party utilities such as Ysearch, Mitosearch, GedMatch, and Open SNP.
Will They Allow You to Upload Your Raw Results?
Again, getting your DNA results into as many databases as possible increases the chance of successful matching. Some companies allow you to enter results from outside DNA tests into their database (for a small fee), while others do not. If you are testing with multiple companies, one of which will not allow you to upload results from another company, then that might be the best company to test with first as direct testing is the only way to be included in their database. If they do allow you to download your raw data, you can then share this with other companies.
What Analytical Tools Do They Offer?
The charts, graphs, and analytical/comparison tools offered by a particular company can be extremely important in helping you to make the best sense of your raw genetic data, and reduce the need for tedious manual analysis. A chromosome browser (not currently offered by AncestryDNA), for example, is an essential important tool for getting the most from your autosomal DNA results as it helps you to identify which portions of your genome you share in common with other individuals. Look for companies which provide as much data and as many tools as possible -- companies which do not allow you access to as many tools and as much data as possible means less return for your DNA dollar.
How Much Does it Cost?
This, of course, is always an important factor, as long as you also consider what you are getting for your money (see points above). If you plan to test with multiple companies, then check prices for both their initial test, as well as the cost for a 3rd-party transfer (transfer of raw genetic data from a test you've had done with another company). Look also for sales around the holidays, National DNA Day, and other times. Sign up for each company's mailing list to be notified of upcoming sales, or subscribe to blogs which focus on genetic genealogy.
DNA Testing for Ethnic & Ancestral Origins?
If your primary interest is in obtaining a percentage breakdown of your ethnic and ancestral origins (countries and regions), the verdict is still out on which test/company to use. These tests compare your DNA to reference samples from around the world to determine which of these your DNA most closely resembles. Because the reference samples available have not yet reached significant levels around the globe, results can vary widely from company to company. This science will continue to advance significantly as an increasing number of people are tested around the world.
Test with More Than One Company for Best Results
Testing with more than one DNA testing company offers the best chance of useful matches. If, however, you can only afford to be tested by one company, or just want to dip your toes into the water slowly, then the International Society of Genetic Genealogists (ISOGG) has fairly up-to-date charts and information in their wiki for comparing the testing offered by different companies to help you choose the right company and test for your goals.
The most important thing you should consider, however, is that getting your DNA (and that of your older living relatives) tested before it is too late is ultimately much more important than which company you decide to test with. Check the ISOGG chart to make sure the company is reputable and provides the tests/tools you most need and you really can't go very wrong.