GENEALOGY-DNA-L Archives
Archiver > GENEALOGY-DNA > 2005-10 > 1130081154
From: David Faux <>
Subject: Re:S21 Ancestral negative (was [DNA] I1a1 & DYS462)
Date: Sun, 23 Oct 2005 08:25:54 -0700 (PDT)
In-Reply-To: <110.550c000f.308cc7c5@aol.com>
Hello Anne:
I used the word "derived" to mean any value away from the ancestral state. This is universal in molecular biology and so I want to maintain consistency and precision. Other companies return results as say "positive at M269G". This is not helpful (well the positive or negative part is) unless you know the strand that the company is using.
If you are ancestral at M17 you will have GGGG at a designated postion (someone who is R1b, M269 would be of this "state"). Derived means "away from" the ancestral state and could be a deletion, insertion, transition or transverstion (nucleotide letter change like say a C to a G or an A to a G) at a designated position on a strand of say 190 nucleotide base pairs as detected by for example direct sequencing (way we do most of our work) or hybridization (used with the multiplex). Thus getting back to my M17 example, the geneticist would see GGGs as there is an indel (in this case deletion) at the postion that defines M17 or R1a1. I use positive and negative because most people know what this means. Thus positive = derived and negative = ancestral. With most markers, being positive is going to be what is informative so if you are M269+ you are R1b1c (R1b3) and now you know your haplogroup. The S21 marker for the moment can be just as informative to be designated negative!
as
positive. In Britain being negative or ancestral at this marker may denoted native Briton and being positive may denote "invader". This is a hypothesis we are actively exploring.
David Faux.
wrote:
In a message dated 10/23/2005 4:18:03 A.M. Central Daylight Time,
writes:
"Ancestral" is the original state. "Derived" is the more recent, changed
state.
If you mutate from A to B, "A" is ancestral, "B" is derived.
I think I'm confused about the results of the R1b sub-group testing.
Here's a quote from the Ethnoancestry page
_http://www.ethnoancestry.com/Prod09.html_ (http://www.ethnoancestry.com/Prod09.html)
"Note that once the data has been collected it may be as informative to be
negative (ancestral) on this marker as it is to be positive (derived)."
Another quote "Currently only three people who are S21 derived or
positive..."
Maybe it's the way the results are reported that is throwing me:
S21 ancestral negative
Seems as if S21 negative (ancestral) and S21 positive (derived) makes more
sense as I read the rest of the site. The above sounds as if one is negative
for S21 ancestral and therefore derived, when my impression is that if one is
negative for S21 one is ancestral instead of derived.. Or do I have this
totally whacked in my mind? If so would David or someone please help me out of
this blackhole I fell into?
Anne
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