Archiver > GENEALOGY-DNA > 2003-11 > 1067715175

From: Ron Lindsay <>
Subject: [DNA] Marker Mutation Rates
Date: Sat, 01 Nov 2003 11:32:55 -0800

Greetings Genealogy-DNA List,

Acknowledging the use of a small sample size (statistically a sin) to fan
the flames coupled with what appears to be "factual" genealogical detail, I
continue to look for legitimate reasons to challenge the current thinking
regarding the assumed Y-chromosome marker mutation rates.

I would like to pose a question to the geneticists and mathematicians
subscribing to this forum.

Is it possible that a fallacy was introduced initially into the thinking
regarding Y-chromosome marker mutation rates based in part on the fact that
marker mutations can move back and forth (+1 or -1) over time and was not
properly taken into consideration by geneticists also using "limited"
database sizes??

Unless someone can tell us that all this probability was indeed factored
into the current "mutation rate equation", is it possible that the markers
could mutate much more often than suspected but this evidence is covered up
due to the fact the DNA that was recorded for a given marker in a paternal
lineage was not recorded for each succeeding generation and thus in many
instances failed to capture a hypothetical +1 marker mutation, for example
at Generation 2, in the lineage which later reverted back to the original
value due to a -1 mutation, for example at Generation 5, in that lineage??
(students of grammer - please forgive the mutations found in the preceding
sentence structure!) If in our analysis, we only tested and compared
individuals with a MRCA merging at Generation 1 and other cousins with a
MRCA at Generation 5 or later, we would totally miss seeing the mutation
that occurred in the lineage at Generation 2 and carried through to
Generation 4.

If we should just happen to test and compare individuals, in the above
scenario, MRCA occurring at Generation 1 with another cousin, MRCA
occurring at Generation 3, without primary genealogical records, it would
lead to a conclusion that their MRCA is further back in time than that
which actually occurred.

If the same +1 to -1 scenario was changed to a +1 to another +1 scenario,
in the hypothetical example above, this would lead to an even more
exaggerated conclusion that these know cousins have a MRCA much further
back in time than actual genealogical records would suggest.

This type of thinking above, in addition to the fact it appears that the
earliest ancestors for most of these participants, originated in Virginia,
North Carolina, South Carolina and Tennessee, was part of the rationale for
my choosing to provide an alternate merger of the Lindsay DNA Groups 3, 4,
5, & 8 (,4,5,8.htm ) , with four
to six marker mis-matches between participants.

Just thinking and looking for possibilities.

Ron Lindsay
San Jose, CA

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