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From: "Carey Bracewell" <>
Subject: [BRASWELL] Probabilities in DNA
Date: Mon, 6 Oct 2003 13:06:34 -0500


Guys--

Anthrogenealogy is about probabilities. It can't tell us names, dates,
or places but only probabilities about genetic kinship. It can't even tell
us degree of kinship, as in the Sally Hemmings case {DNA proved that SOME
Jefferson impregnated her but not WHICH among three or four possible
candidates.} But that information--probability of relationship--is extremely
valuable all the same.

Take Gary Bracewell and me for instance: it's 19 generations
{"transmission events"} back to our first possible common Bracewell ancestor
in Gary's lineage, 14 generations back in mine. 14 + 19 = 33 transmission
events. Given 25 years per generation in back of our oldest known ancestor
and allowing the standard .002 rate of mutation per transmission event,
there should have been at least one mutation (0.8 probability) between
Gary's results and the Carey/Britt Standard. Instead we all match 12/12--
strong biological evidence we all share a common Bracewell male ancestor
born no later than about 1475 A.D. The DNA evidence combined with
documentation indicating a common family origin amounts to proof.

Carey

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