What is a one-step mutation, two-step mutation, etc?
Each step is one mutation, or difference, and is one step further from an exact match. For example, if someone matches you on 11 of 12 markers tested, this person is a one-step mutation from you and probably still shared a common ancestor with you, but in a more distant time-frame than an exact 12 of 12 marker match. A two-step mutation would be a 10 of 12 marker match and would be even more distant. A two-step mutation might also mean that one marker has mutated twice. You can learn more about what these matches mean by checking the FTDNATiP report on your Y-DNA Matches section or by checking here: http://www.familytreedna.com/reading-and-comparing-test-results.aspx.
Each step is one mutation, or difference, and is one step further from an exact match. For example, if someone matches you on 11 of 12 markers tested, this person is a one-step mutation from you and probably still shared a common ancestor with you, but in a more distant time-frame than an exact 12 of 12 marker match. A two-step mutation would be a …
When comparing the results of Y-chromosome STR (short tandem repeat) tests, the difference between the two values at a marker is the number of steps. That is, a one-step mutation means that the count for a single STR has changed by one. A two-step mutation means that the count for a single STR has changed by two. Example: One-Step Mutation Kit Surname Hg D Y S 3 9 3 D Y S 3 9 0 D Y S 1 9 D Y S 3 9 1 D Y S 3 8 5 a D Y S 3 8 5 b D Y S 4 2 6 D Y S 3 8 8 D Y S 4 3 9 D Y S 3 8 9 | 1 D Y S 3 9 2 D Y S 3 8 9 | 2 B193 Sypline I1 12 24 14 10 14 14 11 14 11 12 11 28 B173 Sypline I1 13 24 14 10 14 14 11 14 11 12 11 28 B132 Sypline I1 13 24 14 8 14 14 11 14 11 12 11 28 For example, when comparing kit B193 and kit B173, the STR marker DYS393 has changed from 13 to 12. The difference between 13 and 12 is 1 {13-12= 1.}. This is considered a single or one-step mutation. Example: Two-Step Mutation Kit Surname Hg D Y S 3 9 3 D Y S 3 9 0 D Y S 1 9 D Y S 3 9 1 D Y S 3 8 5 a D Y S 3 8 5 b D Y S 4 2 6 D Y S
