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Archiver > GENEALOGY-DNA > 2005-01 > 1105557336


From: Charles <>
Subject: Male Line Specific Y-STR Average Mutation Rates -- the one size shoe/(haplotypemutation rate) fits all approach is not valid, imo -- corrected URL link
Date: Wed, 12 Jan 2005 14:15:40 -0500


Ernie and others:

As I said the other day and in my discussion and overview article on DNA
mutation rates, in my opinion, the "one shoe size fits all" theory for
the YSTR mutation rate is not satisfactory for analyzing male line
relationships within many surname projects. Too much anecdotal evidence
exists from many surname projects that there are large disparities
between the average mutation rate in one family male line study compared
to another. I believe that Y-STR average mutation rates are more male
line specific, i.e., that some male lines mutate faster than others. Or
the corollary that some Y chromosomes are more stable than others.

If you plotted a histogram for the YSTR mutation rate obtained from the
various male line surname projects, you would probably see a normal
distribution around some center/modal value. That modal value mutation
rate in the center is probably close to the overall Y-STR average
mutation rate for the male population as a whole which is being used by
the various companies. Some think that overall male population average
value is .002, .003, or .004, etc. But an average value for the whole
male population does not determine what your specific male line surname
project average YSTR mutation rates is, or should be. The industry can't
make you where a shoe size that you obviously see doesn't fit for your
project.

I think your project specific male line average rate is determined by
some here-to-now unproven process controlled by the inner working of
your male line Y chromosome. All that junk DNA may not be just junk.

The combination of all the independent male line YSTR mutation rates
determines the modal value and average value of the male population as a
whole. But the average value and modal value for the male population as
a whole does not peg what your surname/male line mutation rate actually is.

A simple example: All the males in a related Smith family have a Y
chromosome 37 marker haplotype that mutates at an average rate of .005.
And the males in a related Jones family have a Y chromosome 37 marker
haplotype that mutates at an average rate of .001. You test a 100 Smith
and 100 Jones males and you get an average rate of .003. But is the
average rate for either family line .003. No it is not. And should
industry guidance plot a nice neat curve on a graph to predict Time to
Most Recent Common Ancestor using the average rate of .003, or whatever
average rate they choose, and then let users think it is the most valid
curve for most families. At this point in time I think not. This is the
problem I see that faces the industry in trying to use the "one
shoe/haplotype mutation rate fits all" method. I think we need more
emphasis on surname project administrators testing enough people to get
an estimate of their male line mutation rate in their project and then
use that mutation rate for the statistical analysis of data in their
project.

The statisticians look at the variance in mutation rates reported by the
various surname projects and say not interesting, not significant,
because the reported average rates for the various surname projects fall
within a certain band or standard deviation from the average value. But
the average value is not the determinate factor in what the Y chromosome
mutation rate is. It is some chemical or other process within the Y
chromosome. and I think each male line Y chromosome is different. One Y
chromosome apparently mutates differently than another. And their is a
broad spectrum of differences. And it is the different mutation rates of
the various Y chromosome male lines that are computed to make up the
average value and standard deviation, not the other way round. Some
folks seem to get hung up on the average rate all the time and cannot
seem to visualize that it is a histogram of distinct data points (the
distinct and different mutation rates from the various Y chromosome male
lines) which computes to determine the average. Whatever the average is
and whatever the standard deviation is, the data points are themselves
still distinct and distributed over some spectrum of values.

The evidence to what I describe above is anecdotal and is provided by
Genetic Genealogists. Here-to-fore, large numbers of family male line
studies had not been done. But the couple thousand Genetic Genealogy
projects are indicating at this point that my theory could be right.
That is one reason I wrote the article on DNA Mutation Rates and
discussed male line specific rates therein. To draw more attention to
this issue and to help Genetic Genealogists realize that they don't have
to force fit their project analysis to one standard overall male
population average rate. And that is why I have been asking others to
help develop a set of tools to instruct surname project admins on how to
calculate their own project specific average haplotype mutation rate as
part of the Log process.
http://www.kerchner.com/dnamutationrates.htm

And that is also why I launched the Surname Projects Y-STR Mutation Rate
Log such that we can start accumulating enough data to get the
geneticists and scientists to take a closer look at this. See the Log. I
ask Surname Project Coordinators who know their Common Male Ancestor and
the Ancestral Haplotype to contribute to the Log. I kicked it off with
my initial entry.
http://www.kerchner.com/cgi-kerchner/ystrmutationrate.cgi

Synergy at Work!

Charles Kerchner
Emmaus PA
http://www.kerchner.com/dna-info.htm


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