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Archiver > DNA-R1B1C7 > 2007-08 > 1186715042


From:
Subject: [DNA-R1B1C7] Network.exe
Date: Thu, 9 Aug 2007 23:04:02 EDT


I think I might have just answered my own question on the figures to use in
Network.exe time calculations.

"0.00069 per locus per 25 years (Zhivotovsky et al. 2004). ..."

If you multiply .00069 X 17 (17 markers) you get .01173

1 divided by .01173 = 85.25

85.25 X 25 years = 2131 years

or

1 mutation every 2131 years

Which is the number Trinity College used in its Network TMRCA calculations.

You can do the same thing for 25 and 37 markers.

25 markers

.01725 (25 markers) 25 years

57.97 X 25 = 1449 years

1 mutation every 1449 years


37 markers

.0255 (37 markers) 25 years

39.2 X 25 = 980 years

1 mutation every 980 years


I then had Network.exe calculate the TMRCA using a 25 marker dataset of
equal numbers of McLaughlins and Ewings, using the standard NW Irish modal as an
ancestral node and chosing every McLaughin and Ewing node as descendant,
regardless of how distant they were from the others of the same surname.

Results:

McLaughin vs. Ewing results
25 markers

4398.75 years (SD 1536) SD 3042 to 5934

2391 BC. (or SD 1035 BC to 3927 BC)

A TMRCA of 4398 years with a standard deviance of 1536 years.

The basic TMRCA would translate to 2391 BC.

The standard deviance would give a range of 1035 BC to 3927 BC).


Can anyone poke some holes in this methodology? Is there something
besides the standard NW irish modal I should be using for an ancestral node? Or
something else I've done wrong? It seems pretty clear this is the method
Trinity College used in analyzing their own 17 marker dataset of Ui Neill surnames
in NW Ireland in arriving at their 1730 year figure TMRCA.

These figures for TMRCA are not far off John McEwen's own projections for
R1bSTR19. If they hold water then the M222+ mutation occurred far before the
time of Nial (d. 405-450 AD).

If any one would like to try this in Network.exe I'd recommend downloading
the latest version. For some reason an older version kept blowing up when I
tried extended marker datasets. The latest version works just fine on 25
markers. Haven't tried 37 yet.


John















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