In
human genetics, 'Haplogroup I1b (S31)' is a
Y-chromosome haplogroup. Its subclade I1b1
★ is typical of
South Slavs, especially
Croats and
Bosniaks. Another subclade, I1b1b (formerly I1b2), is strongly associated with indigenous
Sardinians, but it is also found at low to moderate frequency among populations of the
Basque Country,
Iberia in general,
France, mainland
Italy, the
British Isles, and
Sweden. Contrasting with the tendentially southeastern distribution of I1b1
★ and southwestern distribution of I1b1b, the subclade I1b2 is most commonly found among populations of
Northwest Europe, especially
Denmark,
Germany, the
Netherlands, and the
British Isles.
Subclades
★ I1b (S31)
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★ I1b
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★ I1b1 (P37.2)
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★ I1b1
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★ I1b1a (M26) ''formerly I1b1''
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★
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★ I1b1a1 (M161) ''formerly I1b2a''
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★ I1b1b (P41.2 (M359.2)) ''formerly I1b2''
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★ I1b1b
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★ I1b2 (S23, S30, S32, S33)
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★ I1b2
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★
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★ I1b2a (M223, S24) ''formerly I1c or I2''
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★
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★ I1b2a
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★
★
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★ I1b2a1 (M284) ''formerly I1c1 or I2a''
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★
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★ I1b2a2 (M379)
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★
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★ I1b2a3 (P78)
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★
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★ I1b2a4 (P95)
I1b1
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Haplogroup I1b1
★ (P37.2) accounts for most of the Haplogroup I component in the Y-chromosome diversity of Eastern European populations, reaching its peak in the
Western Balkans, most notably in Dalmatia and Bosnia-Herzegovina (40 - 50 %).
The high frequency and diversity of Haplogroup I1b1
★ among populations of the Western Balkans lends support to the hypothesis that the Adriatic region of modern-day Croatia served as a refuge for populations bearing Haplogroup I1b1
★ during the
last glacial maximum.
I1b1b
Haplogroup I1b1b (P41.2 (M359)), which is found outside of Sardinia only at low frequencies in
Southwest Europe, accounts for almost all of the Haplogroup I Y-chromosomes, which comprise more than 40% of all patrilines among the Sardinians.
A distinct Western European Paleolithic population that bore Haplogroup I1b1b (M26) must have existed somewhere west of the
Apennines in eastern
Iberia, southern
France, or western
Italy, from which it succeeded in the first substantial colonization of the island of Sardinia approximately 9,000 years ago. Despite the fact that the predominantly Sardinian Haplogroup I1b1b-P41.2=M359 is derived from the predominantly Balkan Haplogroup I1b1
★ -P37.2, the derived Haplogroup I1b1b is practically absent east of
France and
Italy, while it is found at low but significant frequencies outside of Sardinia in the
Balearic Islands,
Castile, the
Basque Country, the
Pyrenees, southern and western France, and parts of the
Maghreb,
Great Britain, and
Ireland. Thus, Haplogroup I1b1b appears to be strongly associated with Southwest Europeans of Paleolithic ancestry, and its carriers bear only a distant relictual relationship to the I1b1
★ -bearing populations of the Balkans. It is also interesting that, although the distributions of Haplogroup I1b1b and the predominantly Scandinavian Haplogroup I1a overlap in parts of western France and the British Isles, and both haplogroups appear to have a very long history in Southwest Europe (and particularly France), the populations bearing these two haplogroups appear to have differentiated at a very early date and have not extensively mixed since that time. Haplogroup I1b1b appears to be the only subclade of Haplogroup I found among the
Basques, although subclades of
Haplogroup R1b comprise the vast majority of that people's Y-chromosome diversity. It is notable that Haplogroup I1b1b appears to be found at somewhat higher frequencies among the general populations of
Castile in Spain and
Béarn in France than among the population of ethnic Basques. Lastly, the unique phylogeography of this clade has caused some scientists (Gatto, Michael) to posit that the clade should be associated with the spread of
Chalcolithic Megalith culture in Western Europe. The M26 mutation is found in native males inhabiting every geographic region where megaliths may be found, including such far-flung and culturally disconnected regions like the Canary Islands, the Balearic Isles, Corsica, Ireland, and Sweden. As of 2007, no specific study has confirmed this hypothesis, although the data in several previous studies (Rootsi, et. al., Flores, et. al., etc.) support this hypothesis.
I1b2
The distribution of Haplogroup I1b2 (S23, S30, S32, S33) is closely correlated to that of Haplogroup I1a except in
Fennoscandia, which suggests that it was probably harbored by at least one of the Paleolithic refuge populations that also harbored Haplogroup I1a; the lack of correlation between the distributions of I1a and I1b2 in Fennoscandia may be a result of Haplogroup I1b2's being more strongly affected in the earliest settlement of this region by
founder effects and
genetic drift due to its rarity, as Haplogroup I1b2 comprises less than 10% of the total Y-chromosome diversity of all populations outside of
Lower Saxony. Haplogroup I1b2 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. One subclade of Haplogroup I1b2, namely I1b2a1 (M284), has been found almost exclusively among the population of
Great Britain, which has been taken to suggest that the clade may have a very long history in that island. It is notable, however, that the distributions of Haplogroup I1a and Haplogroup I1b2 seem to correlate fairly well with the extent of historical influence of
Germanic peoples, although the punctual presence of both haplogroups at a low frequency in the area of the historical regions of
Bithynia and
Galatia in
Turkey rather suggests a connection with the ancient
Gauls of
Thrace, several tribes of which are recorded to have immigrated to those parts of Anatolia at the invitation of
Nicomedes I of Bithynia.
Haplogroup I1b2 also occurs among approximately 1% of Sardinians.
See also
★
Haplogroup
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Human Y-chromosome DNA haplogroups
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Haplogroup I (Y-DNA)
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Haplogroup I1a (Y-DNA)
External links
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Phylogeography of Y-Chromosome Haplogroup I
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Frequency and Variance of I1b
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Map of I1b
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Map of 'I1c' (now considered I1b2a)
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'I1c' project at FTDNA
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I1b2 project at FTDNA
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Danish Demes Regional DNA Project: Y-DNA Haplogroup I1b