Ancestry rolled out a major update to its DNA matching system last week, and it's already causing some controversy. According to the company, the new update will improve ethnicity estimates by using a larger reference panel to compare sections of your DNA to identify where you're likely from.
The reference panels are made up of DNA samples from people who have family history in a certain place. The more reference DNA, the more accurate the results will be. But in some cases, customers' ethnicity results appear to have drastically changed. In particular, some women are now being told they have more Vietnamese and Chinese ancestry than they had originally reported.
To address these concerns, Ancestry is urging customers to contact them if they notice any differences in their results. But many customers are angry at Ancestry, saying they had their results ruined and that the new results don't match up with their family trees.
Some of these changes are being caused by an update that's going to take effect in August (exact date unknown). As part of this change, Ancestry will be removing distant matches that share 6cM or less of your DNA. This is going to affect thousands of people. Fortunately, there are ways to keep these matches (details in the lostcousins newsletter and DNA-explained blog).
It's not uncommon for genetic testing companies like 23andMe and Ancestry to update their results on a regular basis. The updates can be minor tweaks to your ethnicity percentage breakdown or more substantial changes such as refinements of existing regions or the addition of new genetic communities. These changes typically take several months to roll out to all customers.