Gosh, Cliff, I question them all the time! Rather than suffer the list to endure my opinions yet again, I've placed them on a web page. Note that not everyone would agree with me, this is just one researcher's opinion: http://dgmweb.net/DNA/y-dna-projects/TMRCA.shtml I prefer to think of the appearance of mutations as the *frequency* of mutations, not the *rate* of mutations, because rate implies even, and random is the *opposite* of even. Diana > -----Original Message----- > From: y-dna-projects-bounces@rootsweb.com On Behalf Of Cliff. Johnston > Sent: Saturday, June 12, 2010 10:16 PM > To: y-dna-projects@rootsweb.com > Subject: Re: [Y-DNA-projects] testing to 67 markers > <snip> > The most important thing to remember is that all mutations > are "RANDOM". Tables giving average numbers of years for > a mutation to occur at a given locus while interesting still > need to be taken "under advisement" as we have several > Cousins with 2 mutations within 3 generations or so. > This makes me question the validity of the mutation > tables...sometimes... > > Good hunting, > > Cliff.

Diana, I read your article and I think it nicely explains a good perspective on TMRCA's. Thank you. I also don't like them when looking at relations with fairly close and close GD's... a handful of people. For similar reasons as you described, I can see personal cases where the TMRCA is misleading. I agree with you it is better used for a large population of people with hopefully some scientific sampling. Regards, Mike On Mon, Jun 14, 2010 at 6:10 AM, Diana Gale Matthiesen <DianaGM@dgmweb.net>wrote: > Gosh, Cliff, I question them all the time! > > Rather than suffer the list to endure my opinions yet again, I've placed > them on > a web page. Note that not everyone would agree with me, this is just one > researcher's opinion: > http://dgmweb.net/DNA/y-dna-projects/TMRCA.shtml > > I prefer to think of the appearance of mutations as the *frequency* of > mutations, not the *rate* of mutations, because rate implies even, and > random is > the *opposite* of even. > > Diana > > > -----Original Message----- > > From: y-dna-projects-bounces@rootsweb.com On Behalf Of Cliff. Johnston > > Sent: Saturday, June 12, 2010 10:16 PM > > To: y-dna-projects@rootsweb.com > > Subject: Re: [Y-DNA-projects] testing to 67 markers > > > <snip> > > The most important thing to remember is that all mutations > > are "RANDOM". Tables giving average numbers of years for > > a mutation to occur at a given locus while interesting still > > need to be taken "under advisement" as we have several > > Cousins with 2 mutations within 3 generations or so. > > This makes me question the validity of the mutation > > tables...sometimes... > > > > Good hunting, > > > > Cliff. > > > ------------------------------- > To unsubscribe from the list, please send an email to > Y-DNA-PROJECTS-request@rootsweb.com with the word 'unsubscribe' without > the quotes in the subject and the body of the message >