Y-DNA Haplogroup I and its Subclades - 2007
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revision date for this specific page: 17 October 2007
Because of continuing research, the structure of the Y-DNA Haplogroup Tree changes and ISOGG
does its best to keep the tree updated with the latest developments
in the field. The viewer may observe other versions of the tree on the Web. Email
Alice Fairhurst if the differences need
I M170, M258, P19,
I* - (unobserved)
I1* - (unobserved)
I1a M253, M307, P30, P40,
S62, S63, S64, S65, S66
I1a1 M227 (formerly
I1b1 P37.2 (formerly I1b)
I1b1a P41.2/M359.2 (formerly I1b1)
I1b1b M26 (formerly I1b2)
I1b1b1 M161 (formerly I1b2a)
S23, S30, S32, S33
S24 (formerly I1c, also shown as I2)
I1b2a1 M284 (formerly I1c1,
also shown as I2a)
- Sims et al (2007) found U250 to be equivalent to M223, but
was not tested against M284, M379, P78 or P95. In addition, U250
is not identical to S31, S23, S30, S32, S33, or S24 nor has it been tested against these SNPs.
- P38 has never been found to be non-redundant with M170, M258, P19, or U179. The
Y Chromosome Consortium in 2002 established the placement of P38 as I1.
- In I1b1a the designation P41.2/M359.2 means that these two SNPs are identical but were discovered
separately. The listing is alphabetical, not necessarily in the order of discovery.
Y-DNA haplogroup I is a European haplogroup, representing nearly one-fifth of the
population. It is almost non-existent outside of Europe, suggesting that it arose in Europe.
Estimates of the age of haplogroup I suggest that it arose prior to the last Glacial Maximum.
Probably, it was confined to the refuge in the Balkans during the last Ice Age, and then spread
northward during the recolonization of northern Europe following the retreat of the glaciers.
There are two main subgroups of haplogroup I:
- I-M253/I-M307/I-P30/I-P40 has highest frequency in Scandinavia, Iceland, and northwest
Europe. In Britain, haplogroup I-M253 is often used as a marker for "invaders," Viking or
Anglo-Saxon. Within I1a, the M227 subclade is concentrated in eastern Europe and the
Balkans and appears to have arisen in the last one thousand to five thousand years. It
has been reported in Germany, Czech Republic, Poland, Estonia, Ukraine, Switzerland,
Slovenia, Bosnia, Macedonia, Croatia, and Lebanon.
- I-S31 includes I-P37.2, which is the most common form in the Balkans and Sardinia, and
I-S23/I-S30/I-S32/I-S33, which reaches its highest frequency along the northwest coast of
continental Europe. Within I-S23 et al, I-M223 occurs in Britain and northwest continental
Europe. A subgroup of I-M223, namely I-M284, occurs almost exclusively in Britain, so it
apparently originated there and has probably been present for thousands of years.
Athey et al,
Resolving the Placement of Haplogroup I-M223 in the Y-chromosome Phylogenetic Tree. (pdf)
Journal of Genetic Genealogy, 1:54-55, 2005.
Capelli et al,
Population Structure in the Mediterranean Basin: A Y Chromosome Perspective. (pdf)
Annals of Human Genetics, 2005.
Cinnioglu et al,
Excavating Y-chromosome Haplotype Strata in Anatolia. (pdf) Human Genetics. 114:127-148, 2004.
Karlsson et al,
Y-chromosome Diversity in Sweden - A Long-time Perspective.
European Journal of Human Genetics, 1-8, 2006. (Comments on paper from Dienekes' Anthropological
Blog - fee for paper from www.nature.com/ejhg)
Rootsi et al,
Phylogeography of Y-Chromosome Haplogroup I Reveals Distinct Domains of Prehistoric Gene
Flow In Europe. American Journal of Human Genetics, 75:128-137, 2004.
Scheinfeldt et al,
Unexpected NRY Chromosome Variation in Northern Island Melanesia. (Link and comments from
Dienekes' Anthropological Blog) Society for Molecular Biology, 2006.
Sengupta et al,
Polarity and Temporality of High Resolution Y-chromosome Distributions in India
Identify Both Indigenous and Exogenous Expansions and Reveal Minor Genetic Influence
of Central Asian Pastoralists. (pdf)
American Journal of Human Genetics, 78:202-221, 2006.
Sims et al,
Sub-Populations Within the Major European and African Derived Haplogroups R1b3 and
E3a Are Differentiated by Previously Phylogenetically Undefined Y-SNPs.
Human Mutation: Mutation in Brief #940, Online, 2007.
Underhill et al,
The Phylogeography of Y Chromosome Binary Haplotypes and the Origins of Modern Human
Populations. (pdf) Annals of Human Genetics, 65:43-62, 2001.
Underhill et al,
Y Chromosome Sequence Variation and the History of Human Populations. (pdf) Nature Genetics, 26:
Y Chromosome Consortium (YCC),
A Nomenclature System for the Tree of Human Y-Chromosomal Binary Haplogroups. Genome
Research, 12:339-348, 2002.
Haplogroup I Y-DNA Project
Ken Nordtvedt, Modal Haplotypes for Y-Haplogroup I
Y-DNA Haplogroup I Subclade I1a
Phil Goff, Deep Ancestry of I1a DYS19=16
I1a and I1b: Frequency Distribution of Extended Haplotypes Gathered from YSearch
Tim Weakley, I1b2* Project Database
Lewis Banks, Y-Haplogroup I1b2 Project
Grant & Jeffrey,
I1c Y-Clan Study (now I1b2a)
Contact People for Haplogroup I: Phil Goff or
Corrections/Additions made since 20 December 2006:
- Email changed for Contact Person on 20 March 2007.
- Added M72 at I1a1a; added S62, S63, S64, S65, S66 on 8 June 2007.
- Added note on P38 under Notes on 8 June 2007.
- Added notation on I* and I1* that they were unobserved on 8 June 2007.
- Removed references to papers by Alonso, Behar, Cruciani, Flores, Kivisild, Nasidze, Shen
and Valone as they neither define the structure nor add to the understanding of Haplogroup I
on 8 June 2007.
- Added references to Underhill, Hammer, YCC, and Sheinfeldt on 8 June 2007.
- Added Ron Scott and Bob Waterouse references in Additional Resources on 8 June 2007.
- Added to third note to Notes on 17 October 2007.