Y-DNA-HAPLOGROUP-I-L ArchivesArchiver > Y-DNA-HAPLOGROUP-I > 2009-03 > 1236807889
From: "Ken Nordtvedt" <>
Subject: Re: [yDNAhgI] A couple of questions that I need help with.
Date: Wed, 11 Mar 2009 15:44:49 -0600
Those are all dated statements that you quote. I2b* became I2b2 with recent
discovery of 4 snps
Going upstream from both I2b2 and I2b1 now, no one is found I2b (one layer
of snps), but a further layer must be traveled upstream to get to the I2*
I estimate branch lines eventually leading to I1 and to I2 separated 22,000
years ago, so we're in the same ball park on that split.
There are over 25 snps now know and phylogenetically equivalent to M253.
They are all strung along a single line of descent for 16 to 18 thousand
years in duration. We don't know the order of those 25 snps or where they
occured in that long stretch. We find not a single haplotype out of many
thousands whose line branched off during that long, long period.
The next thing we know a MRCA about 4000 years ago (not 8000) begins the
quite rapid expansion of the I1 population we see today.
The story over in I2 is more complicated and interesting, but I won't go
into it here. M438 is pinned down to have occured very early after the
initial branching mentioned above. Then quickly after that P37.2+ occured
in a branch line leading to all the I2a.... haplogroups.
So there are no contradictions; just some out-dated information here and
there. Getting back to your M253 question:
M253+ mutation could have happened 22,000 years ago, or 4001 years ago, or
anything in between. We have not the slightest idea. SNP events ARE NOT
DATED by any known technique. Tree nodes are dated. You can bracket the
age of SNP occurrence between an earlier node and a susequent node ---
that's all you can do. Academics who talk about SNP age are confused or
sloppy on this often. They should talk in terms of node ages.
----- Original Message -----
From: "Weldon Smith" <>
Sent: Wednesday, March 11, 2009 3:21 PM
Subject: [yDNAhgI] A couple of questions that I need help with.
> 1. It was stated here recently: There is no known I2b* in the world. I
> am having trouble reconciling that statement with Underhill (2007): "It
> is noteworthy that the I2b-M436* (xM223) representatives occur in north
> and central Europe but at lower frequency than its own derivative clade
> I2b1-M223 ..." These statements seem contradictory, so I think I must
> have missed the point somewhere.
> 2. Rootsi (2004) and Underhill (2007) both state that I1 and I2 clades
> diverged 24-28kya. ISOGG seems to repeat Underhill's ~28kya estimate.
> Does this mean that the MRCA of M253 and M438 lived nearly 30kya? On the
> other hand, one of the SNPs that we use today to mark this bifurcation,
> M253, has an estimated STR variation age of only ~8kya (I haven't seen
> an estimate for the STR variation age of I2-M438.) I read this as: for
> 20K years, I1 populations existed prior to M253. Wouldn't we expect to
> see a large number of SNPs during this long time for which M253 is
> derived? Where are they? Perhaps I misinterpret the term 'STR variation
> age'. What is its meaning?
> Thanks for any helps.
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|Re: [yDNAhgI] A couple of questions that I need help with. by "Ken Nordtvedt" <>|