Thank you for contacting Ancestry in regard to AncestryDNA matches. We apologize for the delayed response, and are happy to help.
We have reviewed your inquiry, and feel that this information may help.As Ancestry continues to improve the accuracy of our DNA matching algorithms, we’ll be changing the way we calculate the amount of DNA that members share with their matches. Here’s what these changes will mean for our members:
More Accurate number of shared segments (Goes live early August)
The DNA you share with a match is distributed across short segments, long segments, or some combination of both. Our updated matching algorithm may reduce the estimated number of segments you share with some of your DNA matches. This doesn’t change the estimated total amount of shared DNA (measured in centimorgans/cM) or the predicted relationship to your matches.
Ability to see the length of the longest shared segment (Goes live Mid-August)
The length of the longest segment you and a DNA match have in common can help determine if you’re actually related. The longer the segment, the more likely you’re related. Segment length is also the easiest way to evaluate the difference between multiple matches that all show the same estimated relationship. Our updated matching algorithm can show you the length of the longest segment you share with your matches.
Distant DNA matches must share 8 cM or higher (Goes live late August)
Our updated matching algorithm will increase the likelihood you’re actually related to very distant matches. As a result, you’ll no longer see matches or be matched to people who share 7.9 cM or less DNA with you unless you’ve messaged them and/or included them in a note, or added them to a group (including your starred group). This means you will have fewer DNA matches and ThruLines™.
Based on customer feedback, we are delaying this change until late August so you have time to review and determine if you want to save any very distant matches by adding them to a group, starring them, adding a note, or sending them a message.
We hope this helps. Thank you for contacting Ancestry. Have a nice day!
If you need additional assistance, please feel free to reply to this message or call us at 1-800-ANCESTRY (1-800-262-3787) between the hours of 9am to 11pm EST, seven days a week.
Customer Solutions Associate