Items below that refer to 12, 25, 37 markers have not yet been revised to mention the 67 now offered by FTDNA. However, in general, the answers remain the same; e.g., results come in different batches, etc.
Note – this page is currently under
The below Q/A are valid – but the numbers need to be revised.
20. Why do some Y DNA surname projects using FTDNA start with a 12-marker test, then upgrade to more markers if there is a match?
21. Are the first 12 markers more important than the others?
22. Are the first 12 markers more stable than the others?
23. I ordered the 25  marker test but the results came in two [three] different batches - and they didn't come in order? Why?
24. On our DNA web site results page I differ from some one on only one marker (DYS 19). Can we assume that a mutation in any DYS/marker could occur in any conception of a male child, perhaps even in two consecutive generations?
25. Many web sites state that the Y chromosome is passed from father to son unchanged, except for a mutation about every 500 generations, but aren't you saying it could happen more often?
26. What's a Haplogroup?
In the beginning, there were only 12 markers available. Later many projects continued to suggest a 12 marker test since it was less expensive. The idea was, if there was not a close match, the participant saved money because he only paid for 12 markers. If there were a close match, then he'd be willing to pay more for the upgrade. Now most project managers recommend testing for at least 25 if the participant can afford it. However, it is a less expensive way to find out if you are close to another participant.
No. The first 12 are NOT more important than the remaining 13 markers. The first 12 were just "discovered" and/or marketed before the remaining 13.
The first 12 are not necessarily more stable than the others. FTDNA reports several "fast moving" (fast mutating) markers and some of these are in the first 12 markers. The markers FTDNA reports as "fast moving" are noted in red on our web site results page. However, administrators of large surname studies report variations that differ from those in the mixed random group.
Yes, this is confusing! The FTDNA lab has three different protocols and runs those tests at different times. They send separate result notices by email for each grouping. They also have assorted terms for these groups. See the first chart (and other information) in After You Test.
24. On our DNA web site results
page I differ from some one on only one marker (DYS 19). Can we assume that a
mutation in any DYS/marker could occur in any conception of a male child,
perhaps even in two consecutive generations?
Yes. Every DYS/marker has the possibility of mutation in any generation. DYS 19's mutation rate is estimated to be .002 (Kayser and Sajantila, 2001), so there is a 1 in 500 chance of a DYS 19 mutation every generation. A rare thing to happen, but it seems to have happened pretty recently in the G1/H1 line. The probability of a mutation occurring in two consecutive generations is very low, but it could happen (and probably has a number of times during human history).
About the mutation rate: There is an average of a 1/500 CHANCE in every generation that a mutation will occur on each marker (not just DYS 19). This way of saying it makes it clear that you could have two generations in a row that mutate, only the probability of that is really, really low: 1/(500*500) = 1/250000 or .000004. It's the same thing really as saying every 500 generations, but the emphasis is on the probability, which is more descriptive.
Also, as noted above, some markers appear to mutate more frequently than others.
Haplogroup usually refers to a "deep ancestry" classification - before surnames were in existence. See Haplogroups.
Note to National Geographic Genographic Project Participants: See your results page at that project web site for more about your haplogroup.
Thank you to J. Kenney, our own personal geneticist, and my husband, T.Bopp (Professor of Chemistry), for help in answering the more technical questions.