Tuesday, February 20, 2018

A rare branch of I-M26 with YCAII=21-21: Updated I-Y11222 tree

Click here to download our February 20, 2018 draft tree for I-Y11222
Click here to download our February 19, 2018 draft tree for I-Y11222

I-M26 is a well known haplogroup because almost 40% of men in Sardinia belong to I-M26.

See this simple tree that shows the fundamental branches of I-M26:
             
     /I-L1274
    |        
 I-M26
    |       /I-Y11222
     \I-Y3992
            \I-L160

(According to the 1000 Genomes project and Francalacci's study of Sardinian Y chromosomes, there may be some additional very rare branches of I-M26 that don't fit into the scheme above).

More than 12 years ago, when people starting doing 37 marker Y-DNA tests for genealogy, we quickly noticed that almost all I-M26 men share the very distinctive marker value YCAII=11-21 or similar . Almost all other men in the world have much higher values: 17-17, 18-21, 19-23 etc.

But there were a few individual I-M26 men who had YCAII=18-20, 21-21 etc. For some of them it was clear that this was a recent mutation, because they had distant male-line relatives with 11-21. But there are some clusters/branches in I-M26 in which all members have 18-20, 21-21 etc.

Thanks to Big Y testing, we now know that the I-L1274 branch diverged from the main I-M26 branch  before the mutation to 11-21. All of I-L1274 has YCA=18-20, 21-21 or similar, and some other distinctive marker values. And almost all of I-Y3992 has YCA=11-21 or similar

But there are some additional branches with YCA=21-21 that don't belong to I-L1274. Recently we received Big Y results for a man with paternal ancestry from Guatemala, he has distant Y-DNA matches to other men from Nicaragua, Mexico etc. They all share YCAII=21-21 and some other distinctive values.

The new Big Y belongs to I-Y11222, and he is additionally Y14718+ Y15473+ and Y14720-. This confirms that the mutation back to YCAII=21-21 was a relatively recent event in his haplogroup branch (within the last 5,000 years): all the other known branches of I-Y11222, I-Y14718, I-Y5473 and I-Y14720 all have the YCAII=11-21.

There is an anonymous sample HG01167 from Puerto Rico who is also M26+ Y3992+ Y11222+ Y14718+ Y15473+ and Y14720 according to the 1000 Genomes project. We will submit this Big Y result to YFull who will compare him to HG01167. There is another Big Y in progress which very likely belongs to this branch.

[February 20 update: we were able to compare the Big Y results to HG01167 and they share 12 variants as shown on our February 20 draft tree which is linked above. We have asked YSeq to add some of these variants to their SNP test catalog]

I-Y11222 is much smaller than I-L160 but it is found in approximately the same places. I-Y11222 doesn't have many branches with large expansions in the last 2,000 years, except for the "M26-France" branches described in our previous post in I-Y11222.



Click here to find our previous tree for I-Y11222 and a post discussing this M26-France group.

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