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Convergence (also known as evolutionary convergence) is a term used in genetic genealogy to describe the process whereby two different haplotypes mutate over time to become identical or near identical resulting in an accidental or coincidental match.[1] Coincidental matches, even at 37 markers, can sometimes be in different subclades and the common ancestor will have lived several thousand years ago rather than within a genealogical timeframe. A case has also been reported of two 67-marker haplotypes with a genetic distance of 6, which were found to be in different R1b subclades.[2]

One might think of convergence as producing "false positive" matches. One would ordinarily interpret a match as indicating a common ancestor but if convergence - rather than inheritance - is operating, there may be no common ancestor. The match is positive but false.

Convergence can be a particular problem for people who have a common haplotype such as the Western Atlantic Modal Haplotype resulting in a large number of matches. In such situations it is recommended to test a minimum of 67 markers. SNP testing should also be ordered to help rule out coincidental matches.

Robert Casey has estimated that perhaps only 5% to 10% of surname clusters are affected by the problems of convergence but for those people in such clusters perhaps 20% to 90% of their matches might be false positives.[3]


Scientific papers

External links

See also


  1. Smolenyak M and Turner A. Trace Your Roots with DNA. Rodale, 2004, p251.
  2. Mayka L. Coincidental convergence (or lack of divergence). Posting on the Rootsweb Genealogy DNA mailing list, 5 November 2012.
  3. Casey R. YSNPs - key to the future. YouTube presentation, 30 October 2013.