Haplogroup I is the oldest major haplogroup in Europe and in all probability the only one that originated there (apart from very minor haplogroups like C6 and deep subclades of other haplogroups). It is thought to have arrived from the Middle East as haplogroup IJ sometime between 40,000 and 30,000 years ago, and developed into haplogroup I approximately 25,000 years ago. In other words, Cro-Magnons most probably belonged to IJ and I (alongside older haplogroups like F and C6).
The I1 branch is estimated to have split away 20,000 years ago and evolved in isolation in Scandinavia during the late Paleolithic and Mesolithic. I1 is defined by at least 25 unique mutations, which indicates that this lineage experienced a serious population bottleneck. Men belonging to this haplogroup all descend from a single ancestor who lived between 10,000 and 7,000 years ago.
During the Mesolithic period, pre-I1 and I1 people were part of the successive Erteb°lle culture (5300-3950 BCE), Funnelbeaker culture (4000-2700 BCE) and Pitted Ware culture (3200-2300 BCE). The latter two are sometimes considered as Neolithic cultures due the introduction of farming. However, Neolithic farmers from Germany penetrated late into Scandinavia and in small numbers, and the lifestyle remained primarily one of hunter-gatherers. This is probably the reason why Scandinavia retained one of the most substantial Paleolithic ancestry in Europe.
How did I1 become Germanic ?
From 2800 BCE, a large-scale cultural and genetic upheaval hit Scandinavia with the arrival of the Indo-Europeans from Eastern Europe, who brought the Copper Age and Early Bronze Age practically without Neolithic transition. The first Indo-Europeans to reach Scandinavia were the Corded Ware people from modern Russia, Belarus and Poland, who are thought to have belonged predominantly to haplogroup R1a. These people carried similar maternal lineages as Scandinavian I1 inhabitants - in great majority mtDNA haplogroups U4 and U5.
The second major Indo-European migration to Scandinavia was that of haplogroup R1b, the branch that is thought to have introduced Proto-Germanic languages, as an offshoot of the Proto-Celto-Germanic speakers from Central Europe. R1b probably entered Scandinavia from present-day Germany as a northward expansion of the late Unetice culture (2300-1600 BCE).
According to the Germanic substrate hypothesis, first proposed by Sigmund Feist in 1932, Proto-Germanic was a hybrid language mixing Indo-European (R1b, and to a lower extent R1a) and pre-Indo-European (native Nordic I1) elements. This hybridisation would have taken place during the Bronze Age and given birth to the first truly Germanic civilization, the Nordic Bronze Age (1700-500 BCE).
Haplogroup I1 is the most common I subclade in northern Europe. It is found mostly in Scandinavia and Finland, where it typically represent over 35% of the male Y-chromosomes.
Associated with the Norse ethnicity, I1 is found in all places invaded by ancient Germanic tribes and the Vikings. Other parts of Europe speaking Germanic languages come next in frequency. Germany, Austria, the Low Countries, England and the Scottish Lowlands all have between 10% and 20% of I1 lineages.
Distribution of haplogroup I1 in Europe
Subclades and Haplotypes
Grouping by STR
All Germanic tribes expanded from a small geographic core around Denmark and southern Sweden within the last 2500 years. STR (short tandem repeats) variations allows to divide I1 members in various categories. There are two main clusters, each with their own subgroups.
- the Northern cluster, peaking in Norway, Sweden and Finland, which corresponds to the I1a2 (L22+, formerly known as I1d) subclade. It normally has an STR value greater than 22 for DYS390.
- the Norse group, corresponds to Ken Nordtvedt's Norse (mostly Swedish) and Ultra-Norse (mostly Norwegian and Icelandic) haplotypes. The Ultra-Norse haplotype 1 (I1-uN1) difers from the Norse one by having DYS385b=15 and (usually) DYS449=29.
- the Bothnian group, is found mostly in Finland and northeast Sweden. It corresponds to I1a2c1 (L258+) subclade, which it makes up 75% of the I1 lineages in Finland.
- the Southern cluster, most common in Denmark, Germany, the Low Countries and the British Isles. It corresponds to Ken Nordtvedt's Anglo-Saxon haplotype (originally Danish and North German).
- the Danish/Polish group usually has a DYS557 value greater than 15.
- the Western group, comprising the Low countries, England, Scotland and Ireland, matches the Z58+ subclade. It probably matches Anglo-Saxon and Frisian/Batavian ancestry.
- there appears to be a specific Welsh subgroup defined by a GATA-H4 value superior or equal to 11. This subgroup is also found in England and on the continent, but is especially common in Wales.
- the German group, is the most common type of I1 in Germany, France, Italy and Central Europe, but is also found in the British Isles and to a lower extent in Scandinavia. It is defined by a DYS456 value inferior to 15. It corresponds to the Z63+ subclade.
- Z131+ is a minor subclade that has been found in areas bordering the ancient Celtic-Germanic boundary (Belgium, central Germany, Bohemia).
- DF29+ represents the vast majority of I1 lineages.
- M227+ has so far been found only in the Baltic countries, Belarus, Poland, Switzerland, France and south-west England (Devon). It has a peculiar distribution lying at the confines of Germanic-speaking regions, although it has never been found in the core of ancient Germanic culture.
- L22+ (aka S142+) is the main Nordic subclade. It is also very common in Britain, especially on the east coast where the Vikings settled most heavily, in the Low Countries and Normandy (also doubtlessly the heritage of the Danish Viking), as well as in Poland and Russia (Swedish Vikings).
- P109+ A mostly southern Scandinavian subclade, with a presence in all the regions settled by the Danish Vikings. It has been found sporadically in many parts of Europe, such as western Iberia, northern Italy, the Balkans, Lithuania and Russia.
- L205+ is mostly limited to the Low Countries, France and Britain. Isolated cases were also identified in Sweden and Spain.
- L287+ is an overwhelmingly Finnish subclade (found nation-wide), with a very small presence in Norway, Sweden, Poland and Russia.
- L300+ is a minor subclade found almost exclusively in southern Finland.
- L813+ is a predominantly Scandinavian subclade, particularly common in southern Norway. It is also found in Britain (likely of Viking descent) and in the northern Netherlands (but not in Germany).
- Z58+ is chiefly West Germanic, with a very strong presence in Germany, the Low Countries and Britain. It is also found to a lower extent in Nordic countries and throughout Continental Europe. Its age has been estimated around 4000 years before present.
- Z138+ (aka Z139+) is a very disparate subclade. It is found at very low frequency throughout the Germanic world, with a peak in England and Wales (although it could just be because of oversampling in Britain). It has also been found in Portugal, southern Italy and Romania. Z138+ corresponds to AS2, AS10, AS1010.2, AS10910, AS1221 and AS1414 and Esc-13 in FTDNA's STR-based nomenclature.
- Z59+ is the main branch of Z58.
- Z382+ has been found especially in the British Isles and Germany, with a minor presence in Scandinavia. Isolated samples were also identified in the Netherlands, Finland, Italy, Croatia and Romania. corresponds to AS3, AS3-911, AS13 and Sw in FTDNA's STR-based nomenclature.
- Z60+ is found throughout the Germanic world
- Z140+ is a strongly West Germanic subclade, found essentially in the British Isles the Low Countries, northern France, central and southern Germany, and Switzerland. It is very rare in Nordic countries. Isolated samples were found in Spain, central and southern Italy, Slovenia, Bohemia, Poland, Ukraine and Russia. Z140* matches the AS5, AS6, AS814 and EE haplotypes in FTDNA's STR-based nomenclature.
- L338+ has a similar distribution to Z140. It typically has the STR value GATA-H4=9. L338+ corresponds to AS1, AS1H, AS8, AS114 and AS11616 in FTDNA's STR-based nomenclature.
- Z73+ (and L1301+) is chiefly northern Scandinavian and Finnish. It is also found in Russia, on the east coast of Britain and the Scottish Isles (Viking heritage). Z73+ corresponds to AS9 and AS16 in FTDNA's STR-based nomenclature.
- L573+ appears mainly North German, with isolated samples in France and Sweden.
- L1248+ (and L803+) is a minor subclade that has been found in Britain, Germany and Russia.
- Z63+ is a strongly German subclade, virtually absent from Nordic countries. It is most common in Central Germany, the Benelux, England, Lowland Scotland, as well as Poland. It has also been found in Russia, Ukraine, the Balkans, Italy, Spain and Portugal.
The Germanic migrations dispersed I1 lineages to Britain (Anglo-Saxons), Belgium (Franks, Saxons), France (Franks, Visigoths and Burgundians), South Germany (Franks, Alamanni, Suebi, Marcomanni, Thuringii and others), Switzerland (Alamanni, Suebi, Burgundians), Iberia (Visigoths, Suebi and Vandals), Italy (Goths, Vandals, Lombards), Austria and Slovenia (Ostrogoths, Lombards, Bavarians), Ukraine and Moldova (Goths), as well as around Hungary and northern Serbia (Gepids). The I1 found among the Poles (6%), Czechs (11%), Slovaks (6%) and Hungarians (8%) is also the result of centuries of influence from their German and Austrian neighbours. The relativelemy high frequency of I1 around Serbia and western Bulgaria (5% to 10%) could be owed to the Goths who settled in the Eastern Roman Empire in the 3rd and 4th centuries.
The Danish and Norwegian Vikings brought more I1 to Britain, Ireland, the Isle of Man, Normandy, Flanders, Iberia, Sicily... The Swedish Vikings (Varangians) set up colonies in Russia and Ukraine, and outposts as far as the Byzantine Empire, the Caucasus and Persia. The higher frequency of I1 in Northwest Russia (east of the Baltic) hints at had a particularly strong Varangian presence, which is concordant with the establishment of the Kievan Rus' by the Swedes.
I1 in Finland
Finland is not a Germanic country linguistically despite having been part of the Kingdom of Sweden for most of its recorded history until the 19th century. Over 60% of Finns belong to the Uralic haplogroup N1c1, which is concordant with the fact that Finnish language (Suomi) also belongs to the Uralic linguistic family. One might therefore wonder whether the 28% of I1 lineages in Finland came from their Scandinavian neighbours (notably Sweden) sometime between the Bronze Age and the Middle Ages, or on the contrary whether I1 spread throughout Fennoscandia at the same time during the Mesolithic period, when the ice sheet receded over the region. A look at the phylogenetic tree shows that the Finns, Swedes and Norwegians belong primarily to the northern cluster (L22). Out of five subclades, two (L287 and L300) are almost exclusively Finnish, while the others are Scandinavian. This is enough to think that a late Mesolithic colonisation of Fennoscandia from Denmark or southern Sweden (perhaps as late as 6000 or 7000 years ago, during the Erteb°lle culture) could have brought I1 around the same time in Finland, central/northern Sweden and Norway. This would have happened well before the first Indo-European speakers reached Scandinavia. Finland is the only country with more than 15% of I1 where the Germanic culture and language didn't take root. A good reason for this would indeed be if Germanic culture did not yet exist in Scandinavia at the time when I1 reached Finland.
Of the 28% of I1 in Finland, 80% belong to the exclusively Finnish L287 and L300 subclades, while the rest (5%) generally resemble more closely Swedish I1. These are typically found on the west and south-west coast of Finland, where Swedes have settled in historical times and where Swedish is still spoken. This is also where most of the R1b (3.5%) and Scandinavian R1a-Z282 (3%) is to be found. The Scandinavian I1 in Finland is found at a similar proportion to R1b and R1a as in Sweden. In contrast, Finnish I1 is found in all the country, where hardly any Germanic Y-DNA is present. This is another confirmation that the I1 in Finland is pre-Germanic, pre-Bronze Age, and consequently of Mesolithic origin.
Unfortunately this timeline seriously conflicts with the estimated age of I1a2c, which Ken Nordtvedt calculated to be only 2000 years old based on STR variatons. This method is not very accurate because it fails to take into account population size. Larger populations create more genetic variations. Nordic countries have always had a lower population density than central of southern Europe. Before the Bronze Age, Nordic people were still hunter-gatherers, while the rest of Europe had been farming for up to 3500 years. Agricultural societies could support populations ten times higher than hunter-gatherers in similar climates. In cold Fennoscandia, the pre-Indo-European population density must have been at least 20 times lower than in Mediterranean Europe. This means that the mutation rate would also be 20 times lower, and therefore that haplogroup I1 is much older than STR variations alone would suggest. If the age estimate of 2000 years old happened to be correct anyway (very unlikely), the only way I1 could have become so predominant in Finland is through an unprecedented founder effect, with a single male lineage quickly replacing one fourth of all lineages in the country (a highly unrealistic scenario).
Malmstr÷ma et al. tested the DNA of Birger Jarl and his son Eric Birgersson, and they were identified as members of haplogroup I1. Birger Jarl was one of Sweden's greatest medieval statesman. He was the founder of Stockholm, and acted as regent of Sweden for 18 years. His sons Valdemar and Magnus suceeded each others as kings of Sweden, and their descendants for one hundred years. This dynasty is known as the House of Bjelbo, and all six kings were presumably members of haplogroup I1.
The Hamilton DNA Project compared the Y-DNA of four descendants of Alexander Hamilton, one of the a Founding Fathers of the United States of America. All shared very close STR values, proving beyond reasonable doubt that they shared a same recent patrilineal ancestor.
The haplogroup of the celebrated Russian writer Leo Tolstoy was inferred by testing one of his descendants, Pyotr Tolstoy.
Calvin Coolidge (1872-1933), the 30th President and 29th Vice President of the United States, was identified as a member of haplogroup I1 according to testing of relatives.
The personal genomics company 23andMe tested the Y-chromosomal haplogroup of business magnate and multi-billionaire Warren Buffett and singer/film producer Jimmy Buffett to determine whether they shared a common patrilineal ancestor. Both men were found to belong to haplogroup I1, though apparently not to closely related subclades.