Gregory wrote: "Please help settle a dispute. "1. A man born in 1658 has 35 repeats at cdy-b. His great-great-grandson born in 1822 has mutated up to 37 repeats at cdy-b. The second man's great-great-grandson born in 1965 has back-mutated to 36 repeats at cdy-b, while two other descendants (one through a different son of the man born in 1822, one through the same) still have 37. "2. The same man born in 1658 still has 35 repeats at cdy-b, but this time his great-great-grandson born in 1822 has only 36 repeats at cdy-b. Two of his descendants through different sons both mutate independently to 37, while a third remains at 36." Others will, no doubt, address the volatility, multi-copy & palindromic aspects of CDY (AKA, DSY724), as well as the reporting of CYDa & CDYb. I'll focus on the epistemology. It is important _HOW_ you "know" the posited values (for CMA b.1658 & GGS b.1822). The dispute may be an artifact of over-interpreting; both scenarios (and others) are plausible. The most likely scenario is not included above; it is that CMA b.1685, & GGS b.1822, had values found in descendants. The men born in 1658 & 1822 can not have been alive in the 21st century for actual Y-DNA testing. Without testing, we can not state their CDY values with any certainty. What can really be known here are the values for the men tested -- i.e., CDYb=37 for two & CDYb=36 for another. Assuming this is the only marker where mismatches are found, it is highly probable that the three men share a CMA within GTF and that that CMA had CDY values of either. As to "back-mutated", this term must be hypothetical or a conclusion. Perhaps, you've "triangulated" (with other descendants) to estimate CDYb values of b.1658 & b.1822. This method yields only probabilistic estimates, with confidence limits unknown to us readers. Conclusion: Neither mutation scenario is more likely than the other on the data provided -- the basis for assumed data is unstated. More likely than either is that CMA b.1658 & GGS b.1822 had CDYb=36 or CDYb=37. -rt_/) AKA, ralph

You've got me with the acronyms, Ralph. Can you please tell me what CMA, GGS, and GTF stand for? Diana > -----Original Message----- > From: y-dna-projects-bounces@rootsweb.com On Behalf Of Ralph Taylor > Sent: Tuesday, June 22, 2010 5:10 PM > To: y-dna-projects@rootsweb.com > Subject: Re: [Y-DNA-projects] Y-DNA-PROJECTS Which mutation > path is morelikely? > > Gregory wrote: "Please help settle a dispute. > > "1. A man born in 1658 has 35 repeats at cdy-b. His > great-great-grandson > born in 1822 has mutated up to 37 repeats at cdy-b. The second man's > great-great-grandson born in 1965 has back-mutated to 36 > repeats at cdy-b, > while two other descendants (one through a different son of > the man born in > 1822, one through the same) still have 37. > > "2. The same man born in 1658 still has 35 repeats at cdy-b, > but this time > his great-great-grandson born in 1822 has only 36 repeats at > cdy-b. Two of > his descendants through different sons both mutate > independently to 37, > while a third remains at 36." > > Others will, no doubt, address the volatility, multi-copy & > palindromic > aspects of CDY (AKA, DSY724), as well as the reporting of > CYDa & CDYb. I'll > focus on the epistemology. > > It is important _HOW_ you "know" the posited values (for CMA > b.1658 & GGS > b.1822). The dispute may be an artifact of over-interpreting; > both scenarios > (and others) are plausible. The most likely scenario is not > included above; > it is that CMA b.1685, & GGS b.1822, had values found in descendants. > > The men born in 1658 & 1822 can not have been alive in the > 21st century for > actual Y-DNA testing. Without testing, we can not state their > CDY values > with any certainty. > > What can really be known here are the values for the men > tested -- i.e., > CDYb=37 for two & CDYb=36 for another. Assuming this is the > only marker > where mismatches are found, it is highly probable that the > three men share a > CMA within GTF and that that CMA had CDY values of either. > > As to "back-mutated", this term must be hypothetical or a conclusion. > Perhaps, you've "triangulated" (with other descendants) to > estimate CDYb > values of b.1658 & b.1822. This method yields only > probabilistic estimates, > with confidence limits unknown to us readers. > > Conclusion: Neither mutation scenario is more likely than the > other on the > data provided -- the basis for assumed data is unstated. More > likely than > either is that CMA b.1658 & GGS b.1822 had CDYb=36 or CDYb=37. > > -rt_/) AKA, ralph > >