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DYS464X results for another Cameron + more L159.2 testing needed

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  • dnalister@comcast.net
    Our recent round of DYS464X test results included results for two Camerons. One that I posted about earlier turned out to be a member of the Leinster
    Message 1 of 1 , Sep 3 7:27 AM
      Our recent round of DYS464X test results included results for two Camerons. One that I posted about earlier turned out to be a member of the Leinster Cluster/BBC with only 1 c type DYS464 marker. This second Cameron does not appear to be closely related to him, but he matches the Leinster Modal Haplotype on 3 markers, DYS389-1, CDYb, and DYS446. That's not a large number of matching key markers, but it's more than the average R-L21 man would match, and two of the markers where he doesn't match are DYS448 and DYS442, which are both markers where we know that some members of the Mystery Group that I discussed in my last message about the McConnell DYS464X test results don't match the Leinster Modal Haplotype, either, so I thought it would be a good idea for this man to do DYS464X testing.

      As it turns out, his result is not ccgg or cggg, but is instead 15c-15c-15g-16c, or ccgc. This is classified as a 3c1g result, and it does not indicate any great likelihood that this Cameron is related to members of the BBC. Having 15 repeats for the g type allele in R-L21 is a little unusual, so it's possible that this man has had some interesting mutations affecting DYS464 markers in his line, but I don't know of a simple sequence of events that would lead to his haplotype from a haplotype that is ancestral to the BBC. In other words, maybe something interesting has happened on his DYS464 markers, but I don't see any reason to think that he is closely related to BBC members and simply had a recLOH mutation that changed his haplotype from ccgg to ccgc. Since his haplotype is somewhat unusual and interesting, I suggested L159.2 testing for this man, and the L159.2 has already been ordered. He will most likely test L159.2-, but in potentially borderline cases like this one, it's good to dig for more information.

      I have added this man to the BeatyByrneMcLaughlin more 3c1g cousins? subgroup of the project. This subgroup is for men who have results on the standard STR tests suggesting that they may be at least distantly related to the BBC, but who have DYS464X test results which do not strongly support such a relationship. Some of the men in this group probably are related to the BBC in the sense that they and BBC members share a common male line ancestor that lived after the time of the R-L21 founder and before the time of the BBC founder. For these men most of the shared key marker values would be the result of shared ancient ancestry and not just pure coincidence.

      We have some other men in the project whose standard test results match the Leinster Modal Haplotype much more closely than the results of men in the BeatyByrneMcLaughlin more 3c1g cousins? subgroup, but who also do not have DYS464X test results that strongly support a relationship. This group is the yellow-green BeatyByrneMcLaughlin more cccg + ccgc cousins? group. Results for members of this group are currently listed just under the results for Mystery subgroup members. In one case (Davidson, kit 150715), the results for a member of this yellow-green group on the ordinary DYS464 test and the DYS464X test do at least suggest the possibility that an unusual recLOH event changed the man's line from ccgg to cccg. So results for Davidson really do suggest that he is a member of the BBC. I have suggested L159.2 testing for him. I think there is a good chance that he would test L159.2+ if tested, and an L159.2+ result would strongly link him to the BBC.

      There are two other men in the yelow-green group that are also likely to descend from the BBC founder. Their DYS464 results do not show the same obvious signs of a possible recLOH event as the Davidson results do, but their haplotypes are so typical for the BBC that we have to consider that possibility that they also descend from the founder of the BBC, but that their lines have had mutations since the time of the BBC founder which have affected their DYS464 markers and DYS464 and DYS464X test results. I would very much like to see L159.2 test results for these other two men, or at least for members of their Cotton and Tyrry families. Such results would help us to better resolve some of our questions about how their lines are related to other BBC lines, and would also give us some indication of the usefulness of L159.2 testing in cases where DYS464X testing is not enough to answer all of our questions. If results for these men did show L159.2 testing to be helpful for exploring relatedness within the BBC, it might be easier for us to encourage L159.2 testing in general, and I think that would be good for our research in the future.

      Cheers,

      Kirsten
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