Haplogroup I2 (Y-DNA)

Haplogroup I2
Possible time of origin probably >15 kya (see subclade descriptions)
Possible place of origin Southeastern Europe
Ancestor I
Descendants I2*, I2a, I2b (see subclade descriptions)
Defining mutations M438/P215/S31
Highest frequencies I2a2 Bosnia and Herzegovina, Croatia, Serbia, I2a1 Sardinia,[1] Basques; I2b1 Germany, Denmark, Netherlands, Belgium, England

In human genetics, Haplogroup I2 is a Y-chromosome haplogroup. Until 2008, it was known as Haplogroup I1b. Haplogroup I2 might have originated in Southeastern Europe some 15,000 - 17,000 years ago and developed into three main subgroups : I2*, I2a, and I2b.

Contents

Subclades

Note: The systematic subclade names have changed several times in recent years, and they are likely to change again, as new markers are discovered which clarify the sequential branching of the tree. The scheme below is taken from ISOGG,[2] which updates (Ytree 2011) Karafet et al. (2008).[3]

Note that the naming of some of the subgroups has changed, as new markers have been identified, and the sequence of mutations has become clearer..

I2

Haplogroup I2 (L68 + M438/P215/S31) is the least common yet one of the oldest haplogroups within haplogroup I, with three main clades: (A) primarily in North West Europe, particularly Scotland and Ireland; (B) in the Caucasus region, with most members in Turkey and Armenia; and (C) in Central Europe. Over the last several years Haplogroup I2 and subclades I2a, I2b and I2c have been confirmed and continue to be developed. However, there is still a group of results that have been classified or predicted as I2*. The Timeline for this split appears to be around 14000 years ago that the I2a split, and shortly thereafter I2a2b and I2a2a parted ways. About 8000 years ago the I2* line split into the three groups A, B and C. The TMRCAs of these 3 groups are believed to be about 2000 to 5000 years ago (approx 50 to 80 generations). More recently a younger Jewish group (J) has branched from group B, which has a TMRCA of centuries (up to 30 plus generations). The actual timeline of the split between groups B and J have not yet been identified.[6][7]

I2a1

Former I2a in the Y2010 tree. The subclade divergence for P37.2 occurred 10.7±4.8 kya. The age of YSTR variation for the P37.2 subclade is 8.0±4.0 kya [8]

I2a1a

Former I2a1 in the Y2010 tree. Haplogroup I2a1a (L158, L159.1/S169.1, M26) accounts for approximately 40% of all patrilines among the Sardinians.[9] It is also found at low to moderate frequency among populations of the Pyrenees (9.5% in Bortzerriak, Navarra; 9.7% in Chazetania, Aragon; 8% in Val d'Aran, Catalunya; 2.9% in Alt Urgell, Catalunya; and 8.1% in Baixa Cerdanya, Catalunya) and Iberia, and it has been found in 1.6% of a sample of Albanians living in the Republic of Macedonia[10] and 1.2% (3/257) of a sample of Czechs.[11] The age of YSTR variation for the M26 subclade has been calculated at 8.0±4.0 kya.[12]

I2a1b

Former I2a2 in the Y2010 tree. I2a1b is very rare, but has been found in two persons from Germany and one from Poland. The age of YSTR variation for the M423 subclade is 8.8±3.6 kya.[13] Pericic places its expansion to have occurred "not earlier than the YD to Holocene transition and not later than the early Neolithic”.[14]

I2a1b1

Former I2a2a in the Y2010 tree. I2a1b1 (L69.2(=T)/S163.2) is typical of the South Slavic populations of south-eastern Europe, being highest in Bosnia-Herzegovina (>50%).[15] Haplogroup I2a1b1 is also commonly found in north-eastern Italians.[16] There is also a high concentration of I2a2a in north-east Romania, Moldova and western Ukraine. In 2010 has Ken Nordtvedt argued that I2a1b1 is too young not to have been a result of a sudden expansion.[17] According to him I2a1b1 arose not earlier than 2500 years ago in Eastern Europe. He has presumed this to be a consequence from the Slavic invasion of the Balkans, from the area north-east of the Carpathians since 500 CE.[18] In 2011 Nordtvedt has confirmed I2a1b1 is not older than 2,800 years.[19] In his last comments about Haplogroup I tree and the conjectured spread map, he locates the start of the I2a1b1 lineage around the middle course of the Vistula.[20]

I2a1b2

Former I2a2b in the Y2010 tree. I2a1b2 (L161) has been found in low frequency in Ireland and Great Britain. Nordtvedt has supposed that around 15,000 years ago the two branch-lines of I2a1b (M423) eventually leading to I2a1b1 (L69.2) and I2a1b2 (L161) separated.

I2a2a

Former I2b1 in the Y2010 tree. I2a2a (M223) has a peak in Germany and another in eastern Sweden, but also appears in Russia, Greece, Italy and around the Black Sea.[21] Haplogroup I2a2a has been found in over 4% of the population only in Germany, the Netherlands, Belgium, Denmark, England (not including Wales or Cornwall), Scotland, and the southern tips of Sweden and Norway in Northwest Europe; the provinces of Normandy, Maine, Anjou, and Perche in northwestern France; the province of Provence in southeastern France; the regions of Tuscany, Umbria, and Latium in Italy; and Moldavia and the area around Russia's Ryazan Oblast and Republic of Mordovia in Eastern Europe. Of historical note, both haplogroups I1 and I2b appear at a low frequency in the historical regions of Bithynia and Galatia in Turkey, possibly descendants of the Varangians, who are historically recorded to have invided those parts of Anatolia from the 9th to 11th centuries. They ventured southwards along the rivers of Eastern Europe, connecting Scandinavia with Constantinople and Byzantine Empire.[22] Haplogroup I2a2a also occurs among approximately 1% of the Sardinians. The subclade divergence for M223 occurred 14.6±3.8 kya (Rootsi 2004). Haplogroup I2a2a can be further subdivided in 5 subgroups. Haplogroup I2a2a* with no further known polymorphisms, Haplogroup I2a2a1 with M284 polymorphism with an undergroup Haplogroup I2a2a1a with the L126/S165, L137/S166 polymorphisms, Haplogroup I2a2a2 with M379 polymorphism, Haplogroup I2a2a3 with P78 polymorphism, and Haplogroup I2a2a4 with P95 polymorphism. The age of YSTR variation for the M223 subclade is 13.2±2.7 kya [23] and 12.3±3.1 kya. [24] Recently two further SNPs were identified L801 continental subclade around 3000 years old and L812 roots.

I2a2a1

Former I2b1a in the Y2010 tree. I2a2a1 (M284) has been found almost exclusively among the population of Great Britain, suggesting that the clade may have arisen in that island. I2a2a1 is comparatively rare in Ireland. Where it is found in those of Irish descent with Gaelic surnames, and particularly in baronial families with a credible pedigree back to a Cruithin (British) origin, this suggests an ancestor who arrived in Ireland from Celtic Britain. For example it is found in McGuinness and McCartan men descended from the Uí Echach Cobha, a lineage considered Cruithin in the 6th century AD.[25]

I2a2a

Former I2b2 in the Y2010 tree. Present day distribution is generally limited to the Upper Rhine and British Isles.[26] Starting from the Upper Rhine, I2a2a-L38 spread during the Early Bronze Age in an area between Rhine, Danube and Elbe and I2a2b-L38 migrated in the Late Iron Age with the Celtic La Tène people, through Belgium, to the British Isles[27] including north-east Ireland.[28]

Haplogroup I2a2a was found in the skeletal remains of Lichtenstein Cave, a Bronze Age archaeological site in central Germany associated with artifacts of the Urnfield culture.[29] Of the 19 males represented in the cave, 15 yielded the full 12 tested STR values, with twelve showing I2a2a, one R1b, and two R1a. Of the 21 females in the cave, the majority were mtDNA H, with mtDNA U5b the runner-up. No radio-carbon dating was discussed and no metrics were assigned based on the adult remains, which are thought to be about 3000 years old. The small sample and their possible familial connections do not permit drawing conclusions regarding the overall contemporary population mixture. However, the cave lies at the center of the area predicted to be high in historical I2a2a population density based on statistical analysis of current population DNA.

See also

Evolutionary tree of Human Y-chromosome DNA (Y-DNA) haplogroups
most recent common Y-ancestor
A
A1b A1a-T
A1a A2-T
A2 A3 BT
B CT
DE CF
D E C F
G H IJK
IJ K
I J LT K(xLT)
L T M NO P S
O N Q R

Y-DNA by populations · Famous Y-DNA haplotypes

References

  1. ^ Siiri Rootsi et al., Phylogeography of Y-Chromosome Haplogroup I Reveals Distinct Domains of Prehistoric Gene Flow in Europe, American Journal of Human Genetics, vol. 75 (2004), pp. 128–137.
  2. ^ ISOGG Haplogroup I
  3. ^ Tatiana M. Karafet et al., New binary polymorphisms reshape and increase resolution of the human Y chromosomal haplogroup tree, Genome Research, doi:10.1101/gr.7172008 PMID 18385274 (2008)
  4. ^ ISOGG 2011
  5. ^ In Search of the Origin of I-L38 (aka I2b2)
  6. ^ World Families Surnames I2
  7. ^ K. Knordtvedt slides on haplogroup I
  8. ^ Siiri Rootsi et al., Phylogeography of Y-Chromosome Haplogroup I Reveals Distinct Domains of Prehistoric Gene Flow in Europe, American Journal of Human Genetics, vol. 75 (2004), pp. 128–137.
  9. ^ S. Rootsi, Y-chromosome haplogroup I prehistoric gene flow in Europe, Documenta Praehistorica, vol. 33 (2006), pp. 17-20.
  10. ^ Vincenza Battaglia et al, Y-chromosomal evidence of the cultural diffusion of agriculture in southeast Europe, European Journal of Human Genetics, vol. 17, no. 6 (June 2009), pp. 820–830, figure 2: Phylogeny of Y-chromosome haplogroups and their frequencies (%) in the examined populations.
  11. ^ F. Luca, F. Di Giacomo, T. Benincasa et al., Y-Chromosomal Variation in the Czech Republic, American Journal of Physical Anthropology 132:132–139 (2007).
  12. ^ Siiri Rootsi et al., Phylogeography of Y-Chromosome Haplogroup I Reveals Distinct Domains of Prehistoric Gene Flow in Europe, American Journal of Human Genetics, vol. 75 (2004), pp. 128–137.
  13. ^ Peter Underhill et al., New phylogenetic relationships for Y-chromosome haplogroup I: Reappraising its Phylogeography and Prehistory, in Rethinking the Human Evolution, ed. P. Mellars et al. (2007), pp. 33-42.
  14. ^ Marijana Peričić et al., High-Resolution Phylogenetic Analysis of Southeastern Europe Traces Major Episodes of Paternal Gene Flow Among Slavic Populations, Molecular Biology and Evolution, vol. 22, no. 10 (October 2005), pp. 1964-1975.
  15. ^ Marijana Peričić et al., High-Resolution Phylogenetic Analysis of Southeastern Europe Traces Major Episodes of Paternal Gene Flow Among Slavic Populations, Molecular Biology and Evolution, vol. 22, no. 10 (October 2005), pp. 1964-1975, Figure 3
  16. ^ Vincenza Battaglia et al., Y-chromosomal evidence of the cultural diffusion of agriculture in southeast Europe, European Journal of Human Genetics advance online publication 24 December 2008.
  17. ^ Genetics of Jews, 6 Jun 2010, Ken Nordtvedt
  18. ^ Russian I2a2a-Dinaric TMRCA, 2010.04.10 by Ken Nordtvedt.
  19. ^ Artificiality of Coalescence Age,6 Jun 2011, Ken Nordtvedt.
  20. ^ K. Nordtwedt's comments about Haplogroup I Tree and conjectured spread map.
  21. ^ Jacques Chiaroni et al., Y chromosome diversity, human expansion, drift, and cultural evolution, PNAS (2009), corrected supplementary information.
  22. ^ http://books.google.com/books?id=H8R9LKwsM8AC&pg=PA7&dq=vikings+baghdad&hl=no&ei=NEnETdXJE8Tk4gbl8qWpBQ&sa=X&oi=book_result&ct=result&resnum=8&ved=0CFsQ6AEwBw#v=onepage&q=vikings%20baghdad&f=false
  23. ^ Siiri Rootsi et al., Phylogeography of Y-Chromosome Haplogroup I Reveals Distinct Domains of Prehistoric Gene Flow in Europe, American Journal of Human Genetics, vol. 75 (2004), pp. 128–137.
  24. ^ Peter Underhill et al., New phylogenetic relationships for Y-chromosome haplogroup I: Reappraising its Phylogeography and Prehistory, in Rethinking the Human Evolution, ed. P. Mellars et al. (2007), pp. 33-42.
  25. ^ B.P. McEvoy and D.G. Bradley, Irish Genetics and Celts, Celtic from the West (2010), p.117. They identify this haplogroup as I1c, the old name of its parent.
  26. ^ In Search of the Origin of I-L38 (aka I2a2a)
  27. ^ De Beule, Hans (2010). "Early Bronze Age Origin and Late Iron Age (La Tène) Migrations of I-L38". The Russian Journal of Genetic Genealogy 1 (2): 47–55. http://docs.google.com/viewer?a=v&pid=sites&srcid=ZGVmYXVsdGRvbWFpbnxoYXBsb2dyb3VwaWwzOHxneDo3NjRhODJlMTZhNTI3MTU0. Retrieved 8 May 2011. 
  28. ^ McEvoy and Bradley, Brian P and Daniel G (2010). Celtic from the West Chapter 5: Irish Genetics and Celts. Oxbow Books, Oxford, UK. pp. 117. ISBN 978-1-84217-410-4. 
  29. ^ Lichtenstein Cave Data Analysis | Ken Nordtvedt: "The Lichtenstein cave ydna haplotypes show three from the new S23+(xM223) I2b* (ISOGG 2008) tree"

External links

Projects

Relationship to haplogroups and subclades

Evolutionary tree of Human Y-chromosome DNA (Y-DNA) haplogroups
most recent common Y-ancestor
A
A1b A1a-T
A1a A2-T
A2 A3 BT
B CT
DE CF
D E C F
G H IJK
IJ K
I J LT K(xLT)
L T M NO P S
O N Q R

Y-DNA by populations · Famous Y-DNA haplotypes
Haplogroup I
I1

I1a


I1b


I1c


I1d


I1e


I2

I2a


I2b


I2*