When asked about how database size affects ancestry results, David Nicholson, co-founder of Living DNA, told us, “The tests absolutely rely on the reference database. If you have Polish ancestry but there are no people in the database who are Polish, then what the test will do is show what the next closest group is next to Polish, like German or Eastern European ancestry.” Each ancestry DNA service has its own sample database and reference panel made of the DNA samples collected from their users and information collected from sources like the 1000 Genomes Project. The database consists of all this information collectively. A reference panel is made of certain curated samples with known family history and roots in a specific place. The services use insights gleaned from the reference panel to give you geographical ancestry results. In theory, a larger database leads to more information available to create a good reference panel, which then leads to better results for customers.  
It may cost a little more, but I would highly recommend saving the extra and using DNA Tribes® rather than spending over half the cost for minimal tribal/biogeographical pinpointed information. The primary benefit of STR rather than SNP testing is the availability of rich reference data. DNA Tribes® tests industry standard autosomal STR systems, which allow the identification of a person’s DNA profile not shared with any other person. Because these STR markers have been tested and used in the court systems around the world, they allow DNA Tribes® to perform the most thorough comparison of a person’s own DNA profile to over 1,200 ethnic groups (populations) around the world. At present, SNP testing from these other autosomnal DNA testing kits does not yet match the geographical detail of DNA Tribes® autosomal STR analysis.
Hi Mark, Thank you for your article – very helpful. I am adopted from Asian country and live in Australia. I don’t know who my biological parents are and don’t know if I have any siblings. I have been researching through all these websites trying to decide which dna test to take – confused by it all. Your article has helped me to decide on FTDNA (family history and mtDNA) – hoping that it would give me ancestry makeup inherited from my bio parents and ancestry details on my mothers side (as I am female, limited to this test). In… Read more »
It’s easy to do these tests; it’s usually just a case of collecting your own samples at home, filling in short, basic questionnaires, posting the packages, and then logging on to interactive websites for confidential results (all the kits I tested used outside laboratories). With an array of price ranges and options, from one-off DNA-blitzes to targeting specific health areas, to fitness/wellness tracking, it’s no surprise that these kits are proving to be very big business and the field is primed to get even bigger, with a global market estimated to be worth around £7.7bn by 2022.