GENEALOGY-DNA-L ArchivesArchiver > GENEALOGY-DNA > 2009-03 > 1237745267
From: (John Chandler)
Subject: Re: [DNA] Fw: age of haplogroups
Date: Sun, 22 Mar 2009 14:07:47 -0400
> Second, who needs it? When we calibrate mutation rates, we use
> years, not "a number of generations".
No. By far the best determinations of mutation rates, both in terms
of nominal statitical uncertainty and of "complicating factors," are
those based on direct observation of mutations in father-son pairs.
In these observations, the number of generations is fixed at 1, and
the "genetic distance ladder" is thus firmly anchored in a time
reference of generations, not years. Indeed, these observations have
been analyzed to look for a correlation between mutation and father's
age, but no such pattern has been established. That's why the
anthropological studies of patterns of reproduction-vs-age in modern
hunter-gatherers (among others) are crucial in helping to calibrate
the generations-to-years conversion.
|Re: [DNA] Fw: age of haplogroups by (John Chandler)|