Haplogroup I-M170

In, Haplogroup I (M170, P19, M258) is a.

Haplogroup I (the letter I, not the number 1) can be found in most present-day European populations, most commonly in, , and the populations of the  in southeastern Europe.

According to current theories, Haplogroup I first arrived in Europe around 20,000-25,000 years ago from the, perhaps associated with the  culture, and just prior to the onset of the  (LGM). It is most closely related to ,the "Semitic marker" being the most common in Semitic peoples, as both Haplogroup I and Haplogroup J are descendants of Haplogroup IJ (S2, S22). Haplogroup IJ is in turn derived from. The Haplogroup I Y-chromosomes found among the Scandinavians, Sardinians, and Slavs generally belong to different s, however (Rootsi et al. 2004), which indicates that each of the ancestral populations now dominated by a particular subclade experienced an independent population expansion, believed to reflect different migrations of people during and immediately after the ice age. Two main subgroups of are I-M253/I-M307/I-P30/I-P40 which has highest frequency in Scandinavia, Iceland, and northwest Europe. The other is I-S31 which 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.

Haplogroup I Y-chromosomes have also been found among some populations of the Middle East, the Caucasus, and Central Asia, but they are found at frequencies exceeding 10% only among populations of Europe and Asia Minor, particularly among, , , and , as well as among the -speaking populations of , , , and , the -speaking population of , and the -speaking population of.

Within Europe, several populations are distinguished by having a significantly lower frequency of Haplogroup I than the surrounding populations: these depressions in the frequency of Haplogroup I distinguish the populations of and  from  and,  from southern  and ,  from  and the , and the   from the. Thus, it could be said that Haplogroup I displays relatively higher frequencies among peoples who have at times been considered to be "northern barbarians". The great majority of the Y-chromosomes among even these "northern barbarians," however, is composed of the same haplogroups (R1b in Western Europe, R1a1 in Eastern Europe, and N in Northeastern Europe) as the majority of the Y-chromosomes of the southerly, earlier civilized populations.

Subgroups
The s of Haplogroup I with their defining mutation, according to the 2006 ISOGG tree:


 * I (M170, M258, P19)
 * I*
 * I1 (P38)
 * I1*
 * I1a (M253, M307, P30, P40) Typical of populations of and, with a moderate distribution throughout 
 * I1a*
 * I1a1 (M227) Appears to be limited to a marginally low frequency of approximately 1% among and  of ; also detected in a single  man
 * I1a1a (M72)
 * I1a2 (M21)
 * I1b (S31)
 * I1b*
 * I1b1 (P37.2) Typical of the of the, especially the populations of  and ; also found with high haplotype diversity values, but lower overall frequency, among the West Slavic populations of  and the ; a node of elevated frequency in  correlates with that observed for Haplogroup I1b2 (but not for Haplogroup I1a)
 * I1b1*
 * I1b1a (M26)
 * I1b1a1 (M161)
 * I1b1b (P41.2 (M359.2)) Typical of the population of the so-called "archaic zone" of ; also found at low frequencies among populations of Southwest Europe, particularly in, , and the 
 * I1b1b*
 * I1b2 (S23, S30, S32, S33) Occurs at a moderate frequency among populations of Northwest Europe, with a peak frequency in the region of in central ; minor offshoots appear in  and  (especially around, , , and the )
 * I1b2*
 * I1b2a (M223, S24)
 * I1b2a*
 * I1b2a1 (M284) Generally limited to a low frequency in 
 * I1b2a2 (M379)
 * I1b2a3 (P78)
 * I1b2a4 (P95)

''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. Names from older literature which have now been superseded include: I1b (P37.2) now I1b1 — I1b2 (M26) now I1b1b — I2 (M223), later I1c (M223) now I1b2a —  I2a (M284), later I1c1 (M284) now ''I1b2a1. Future changes may occur, according to Ken Nordtvedt , if the P38 SNP is made equivalent to the M258, P19, and M170 ''SNPs. Which would change I1a to I1, I1b1 to I2a & I1b2a to I2b.''

I*
The composite subclade I* contains individuals directly descended from the earliest members of Haplogroup I, bearing none of the subsequent mutations which identify the remaining named subclades.

Several haplogroup I* individuals, with some of the greatest Y-STR diversity, have significantly been found among the populations of (8/741),  (2/138), and  (1/176), even though as a whole Haplogroup I occurs at only very low frequencies among modern populations of the Middle East and Caucasus. This is consistent with the belief that the haplogroup first appeared in that region. Overall, the highest frequencies of Haplogroup I* appear to be found among the (3/103),  (4/179),  (2/55), and the  (1/35).

I1a
Haplogroup I1a (M253, M307, P30, P40) displays a very clear frequency gradient, with a peak frequency of approximately 35% among the populations of southern, southwestern , and , and rapidly decreasing frequencies toward the edges of the historically -influenced world.

Outside, distribution of Haplogroup I1a is closely correlated with that of Haplogroup I1b2; but among Scandinavians (including both Germanic and Uralic peoples of the region) nearly all the Haplogroup I Y-chromosomes are I1a. Another characteristic of the Scandinavian I1a Y-chromosomes is their rather low diversity (STR diversity): a greater variety of Haplogroup I1a Y-chromosomes has been found among the  and, despite the much lower overall frequency of Haplogroup I1a among the modern French and Italian populations. Taken together, this suggests that the Haplogroup I element of the ancestry of Scandinavians might be descended from a very small Paleolithic population of Southern European extraction, which became distinct from the ancestral population of Haplogroup I1a individuals outside Scandinavia.

It is conjectured that this shared ancestral population of I1a and I1b2, distinct from I1b1*, may have weathered the last ice age in a refuge located somewhere in the or southern, or perhaps the ; after the end of the ice age, some of them headed northward and repopulated Northwest Europe and Scandinavia. This population appears to have carried haplogroups I1a and I1b2 at significant frequencies, with a numerical superiority of Haplogroup I1a. Their descendants are primarily found among the, , and ic populations of Northern Europe, although almost always overshadowed by the more prevalent carriers of. If R is considered more specifically, as it is, split between R1b & R1a, then I1a shares almost equally the areas of population where it is at its peak frequencies.

I1b1*
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, most notably in and  (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.

I1b1b
Haplogroup I1b1b (M359), which is found outside of Sardinia only at low frequencies in, 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 in eastern, southern , or western , 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-M359 is derived from the predominantly Balkan Haplogroup I1b1*-P37.2, the derived Haplogroup I1b1b is practically absent east of and, while it is found at low but significant frequencies outside of Sardinia in the , , the , the , southern and western France, and parts of the  in , , and. 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, although subclades of 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 in Spain and  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  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, 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 s and due to its rarity, as Haplogroup I1b2 comprises less than 10% of the total Y-chromosome diversity of all populations outside of. Haplogroup I1b2 has been found in over 4% of the population only in, the , , , (not including ), , and the southern tips of  and  in Northwest Europe; the provinces of , , , and  in northwestern ; the province of  in southeastern France; the regions of , , and  in ; and  and the area around Russia's  and  in Eastern Europe. One subclade of Haplogroup I1b2, namely I1b2a1 (M284), has been found almost exclusively among the population of, 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, although the punctual presence of both haplogroups at a low frequency in the area of the historical regions of and  in  rather suggests a connection with the ancient  of , several tribes of which are recorded to have immigrated to those parts of Anatolia at the invitation of.

Haplogroup I1b2 also occurs among approximately 1% of Sardinians.