All AncestryDNA customers to some extent, but especially Jewish and Hispanic customers, have been getting false cousin matches (nice of them to let us know about this now).
If you were of Jewish or Hispanic ancestry, most AncestryDNA autosomal testers received matches which seemingly would indicate they're cousins with everyone else of the same ethnicity. Ancestry.com's DNA team explains in an August 1, 2014, announcement why these false matches can happen.
All humans are genetically 99 percent identical, so there are two reasons that two people might have identical DNA. As I explained last Spring in our TCCC DNA class, your DNA chromosome matches can be the result of either an IDB or IDS chromosome match.
IDB: The autosomal DNA is "Identical By Descent," meaning the two people it belongs to are related
IDS: The autosomal DNA is "Identical By State," meaning that the two people it belongs to are simply of the same ethnicity or are at a minimum both human (duh!).
It can be difficult to ferret out the DNA segments that are IDB from those that are IDS, but according to this announcement by the AncestryDNA team they have developed a new way to analyze results that can tell the difference.
According to this informational release, in the coming months, "all customers will see increased accuracy of their DNA matches, and significantly fewer 'false' matches." Existing customers will receive an email when their new matches which are more accurate are ready for review.
You can read more about this coming feature on the Ancestry.com blog at
AncestryDNA to Improve Cousin Matching
I hope to have more information on this very soon, and will probably be discussing this in more detail in my Ancestry.com class starting on August 21 on the TCCC Main campus in Peachtree, North Carolina. If you are interested signing up for for that class, seats are filling fast, so contact the director of community enrichment class, Lisa Long at (828) 835-4241 to reserve your seat.
