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Subject: Re: [DNA] Experimenting with Family Finder Chromosome Browser
Date: Sat, 18 Sep 2010 11:03:29 -0400


Congratulations to CeCe Moore who sequenced the four ancestors, A,B,C and D on another list as follows:


Anna- T,G,T
Barnhart - G,T,T
Conrad- T,T,G
Deitrich- G,G,G
----
In other words, these are the correct two strands each:
Cousin 1 is AB = TGT plus GTT
Cousin 2 is BC = GTT plus TTG
Cousin 3 is AC = TGT plus TTG
Cousin 4 is AD = TGT plus GGG
Cousin 5 is BD = GTT plus GGG
Cousin 6 is CD = TTG plus GGG


Note that these cousins get matching sequences from both maternal and paternal sides of the family in the same segments. The two homologous chromosome sequences have been clearly identified through identification of mismatches. It is through the process of illimination. You must know who the ancestors were and you must be able to untangle the raw data. When I say "cousin", remember that each person shows one other non-cousin.


Another possible set of sequences was brought to my attention off-list which met some of the criteria but not all of the criteria. I did not include all the criteria in every message so it was likely just overlooked. Here Cousins 1, 2 and 3 were supposed to have multiple ancestors, each inheriting two out of the three common ancestral sequences. However, the following sequences show that Cousins 1, 2 and 3 all have the same one ancestor in common (not 3). People usually assume they should have only one ancestor in common, not three because that is the norm. I'll include the sequences because it gives a very important lesson:


Cousin 1 is GGT plus TTT
Cousin 2 is TTT plus GTG
Cousin 3 is TTT plus TGG
Cousin 4 is TGG plus GGT
Cousin 5 is GTG plus GGT
Cousin 6 is GTG plus TGG


Here are the original 6 cousins' results provided by Greg:
> 1: GT, GT, TT
> 2: GT, TT, GT
> 3: TT, GT, GT
> 4: GT, GG, GT
> 5: GG, GT, GT
> 6: GT, GT, GG


What I think is striking is that you could come up with an entire group of six erroneous ancestral sequences if you don't identify the exact ancestors who are attached to each pedigree, hence each sequence. It really underscores the importance of getting great genealogists to contribute their hard work with accurate pedigrees to this kind of genetic information.


Kathy J.



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