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From: "Ken Nordtvedt" <>
Subject: [yDNAhgI] The Younger Dryas Nine
Date: Sun, 2 May 2010 12:55:55 -0600


Straddling 12,000 years B.P., Europe and nearby regions experienced a prolonged cold period of over a thousand years duration --- the Younger Dryas. It was probably the most recent severe demographic setback our ancestors around Europe experienced. Although y haplogroup I (y-Hg I) was by then a mature-in-age haplogroup, being perhaps 10,000 years old already, I conclude from collecting and examining between five and ten thousand haplotypes of y-Hg I today that only nine males emerged from Younger Dryas with surviving male-line descendants today. These Younger Dryas Nine now have tens of millions of male descendants in Europe and elsewhere on the globe where Europeans have settled in recent centuries.

These nine Hg I males were ancestors, indeed very ancient ancestors, of various European* haplogroup TMRCAs (founders) with present population names:

I1
I2*
I2a*
I2a1
I2a2a
I2a2b
I2a3
I2b1
I2b2

Note: There are no known haplotypes today of haplogroups I* and I2b*; this is an artifact to some degree of the accidental order of y-SNP discoveries and the haplogroup naming rules --- today's inventory of known y-SNPs being just a drop in the bucket compared to all existing y-SNPs in the phylogenetic tree. The tree, drawn to time scale, without the names on it, more closely represents the nature of our phylogenetic knowledge today.

12,000 B.P. each of these nine males were not alone; each was living in a surrounding hunter-gatherer male population of immediate family, extended family, clan, tribe, etc. Some of these neighboring males carried y haplotypes very close to one of the nine and descended from common ancestors not too much further back in time. These clades of haplotypes surrounding each of the nine could be counted in the tens, hundreds, maybe even thousands of contemporaries.

But due to very high extinction probabilities for these male lines, exceeding 99 percent, these nine lucky ones emerged as sole representatives of their clades having surviving lines today. Many y-clades no doubt went completely extinct in that era.

In the coming weeks I will construct a somewhat speculative narrative of where these nine males may have been living 12,000 B.P., but will then tie them to their known descendant clades of today which ended with distinct geographical distributions in Europe.

* I2* also has a decent population today in eastern Anatolia and on into the Caucasus. This is the only clade or sub-haplogroup of Hg I with a likely outside-of-Europe indigenous population.

Ken


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