To add clarity to this discussion, it must be noted that the demonstration posted regarding the generation issue is that METHODOLOGY is everything. The demonstration also clarified that with the Klyosov/Rozhanski method whether 3 or4 generations is used in the formulas employed for the different considerations, because the method has already been calibrated and allows for the nuances of the quirky haplotypes in both the consideration of the mutation rate constant (which is tied to the statistical generation) and the method of mutation count that the resulting TMRCA of any given set will be the same -- with either the 30 or 25 year statistical generation. In short using The 30 year generation mutation rate constant per haplotype of .2376 (by the marker .0021405) for 111 marker haplotype; the 30 year generations .144 mutation rate constant per haplotype (by the marker .002149267) for the 67 marker haplotype OR 25 year generation mutation rate constant of .198 per haplotype for the 111 marker haplotyes (by the marker, .00178378); the 67 marker constant per haplotype of .12 (.001791044 per marker) for the 67 marker haplotype -- The result will be exactly the same if the method is being used properly. To reiterate a comfort zone here, Michal Milewski, co-admin of the R1a1a and Sub-clades project in his day job is * Michał Milewski (Poland) Researcher in the field of medical genetics and cell biology. Ph.D. in Medical Biology. Regarding YDNA Admin of Z280 section, Eurasian subclades. As mentioned, he's been working also TMRCA estimates using SNPs and noted that the Klyosov/Rozhanski methodology is consistent with the new SNP based methods in results for TMRCA (see quote from my previous posting). Michal and I communicate frequently. We are in good stead with the Klyosov/Rozhanski method. And for those who may wonder if I interpret the method correctly: I became acquainted with Dr. Klyosov in 2011 and under his supervision in the application of the method from the latter quarter of 2011 through the early months of 2014, invited in 2013 to be part of his research group and a contributor to his DNA Genealogy publications effort, etc. He is the publisher of "Not All Scots were Irish First" that I authored in addition to numerous other discussions regarding the method and its use. You may look at Klyosov's credentials here http://aklyosov.home.comcast.net/~aklyosov/ You may read also about him here http://en.wikipedia.org/wiki/Anatole_Klyosov Susan . On 5/21/2014 1:57 PM, Paul Conroy wrote: > The latest paper on dating based on STR's put a generation length at 31 t0 > 32 years. > > Paper: > http://biorxiv.org/content/early/2014/05/03/004705 > > Discussion: > http://dienekes.blogspot.com/2014/05/genealogical-vs-evolutionary-y-str.html > > > > >