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Archiver > GENEALOGY-DNA > 2006-08 > 1155081589


From: "William Hurst" <>
Subject: RE: [DNA] re mit search
Date: Tue, 08 Aug 2006 19:59:49 -0400
In-Reply-To: <44D91C10.6010604@charter.net>


John wrote:
>
>It occurs to me that the unrefuted response I got from one of the wonks on
>the list the other day can't be true. Either that or the presence of the
>various mitochondrial search engines is nonsense. I asked (paraphrasing)
>if there are modals for the various haplogroups so one could estimate their
>haplogroup from their profile of mutations. Someone answered there aren't.
>Now if that's true, then if someone matches with someone else it means
>nothing because they might be entirely different haplogroups. Now it seems
>to me that similar profiles ought to be more concretely associated with
>certain haplogroups since the mutation is so much slower so there are many
>fewer coincidental matchings and there are many fewer reverse mutations
>back to the original.
>JAL

John, I can only speak for mtDNA haplogroup K. If we define "modal" as
simply the most common, K probably has a modal; but it would be meaningless.
That's almost the opposite way that Y-DNA works, where the modal and the
ancestral are often the same. (That's the way it works in our Hurst Group A
out to 67 markers.) What K does have is an ancestral haplotype composed of
six HVR mutations which almost every K has. However, no K has just those six
mutations. That means there have been no "back mutations to the original,"
even though mtDNA has lots of back mutations. Every K sequence that I have
seen - and I've seen a lot - has at least one more mutation. And there are a
lot with just one more mutation, usually either 497T and 146C.

You also have to realize that for most of the sequences we see are only HVR
sequences, which only represents about 1045 of 16569 of the total positions
on mtDNA. Therefore it is certainly possible for matching HVR haplotypes to
be in different haplogroups, especially for those close to the CRS. The
haplogroups are officially determined by coding-region mutations. I've heard
that FTDNA tests all sequences now for about 20 coding-region mutations to
accurately assign haplogroups. I doubt if other companies do the same.

Bill Hurst



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