Genetic studies on Sami

Since the early years of genetic research, the Sami people have caught the interests of scientists. The Sami languages belong to the Uralic languages family of Eurasia. Some earlier anthropologists have suggested they might be of Asian and/or Siberian origin. The frequency of blood group and protein polymorphisms in Sami differs significantly from the general Northern European population.[1]

In more recent years the use of mitochondrial DNA (mtDNA) and Y-DNA chromosomal markers has offered the opportunity for clarification of the origin of the Sami. While their mtDNA haplogroup distribution overwhelmingly represents a subset of the European gene-pool, the most common Y-DNA haplogroup among the Sami is widely believed to be of Eurasian origin and very common among all peoples in northeastern Europe, which is Haplogroup N-M231 and its subclades. Some research shows that the second most common haplogroup is Haplogroup I-M170, which is found almost exclusively among those of European ancestry.[2] Haplogroup I in Sami, at least 38 Sami in Sweden, is dated to the 14th century,[3] so quite late in Sami (genetic) history. In the study were only those 38 Sami tested. The problem with that study is that it does not reveal all the different haplogroups in each of the individuals. Instead it seems that if a person tested for haplogroup I as dominant, that person has been labelled as solely belonging to that haplogroup, not accounting for any other haplogroup in that individual.

Nevertheless, the Sami appear to have a complex population history, suggesting a mixture of peoples arriving in Fenno-Scandia at different times, from different directions. Strangely, this small admixture of peoples has also remained homogeneous within the Saami for several millenniums thereafter. This in-turn suggests that Sami has not intermarried or mixed much with other surrounding ethnic groups.

Other research on Sami shows that most of them have no belonging to the (somewhat) mysterious mtDNA Haplogroup I.[4] (Not to be confused for the aforementioned paternal Haplogroup I-M170.) This is uncanny; because it is unlike the Finns and Sami's other companions that share Uralic heredity. This could suggest that Haplogroup I (along with Haplogroup W) are perhaps mitochondrial fraternals; and may have only spread conservatively through Northern Europe and the Uralic peoples via contact with Indo-Europeans; during the late Neolithic. If Sami had carried Haplogroup I in relatively ancient Sami populations; this would imply that any acquired Indo-European maternal admixture within the Sami were relatively small. And their Indo-European lineages; unlike Haplogroup W, could have easily become rarer or extinct over time. (Both Haplogroup I and Haplogroup W are descendants of the Eurasian Macrogroup N, and are usually found and observed in Europe at trace frequencies in similar spots almost like counterparts - perhaps in areas where Indo-Europeans had settled.) Even the non-Indo-European Basques carry haplogroup I and W in small frequencies, hand-in-hand—But not in the Sami. Even stranger, is that the few Sami who have intermixed with other Scandinavian peoples (Norwegians, Finns or Swedes, for instance) still seem to lack a significant proportion of mitochondrial I.

mtDNA Haplogroups

Classification of the Sami mtDNA lineages revealed that the majority are clustered in a subset of the European mtDNA pool. The two haplogroups V and U5b dominate, between them accounting for about 89% of the total. This gives the Sami regions the highest level of Haplogroups V and U5b thus far found. Both haplogroups V and U5b are spread at moderate frequencies across Europe, from Iberia to the Ural Mountains. Haplogroups H, D5 and Z represent most of the remaining averaged total. Overall 98% of the Sami mtDNA pool is encompassed within haplogroups V, U5b, H, Z, and D5. Local frequencies among the Sami vary.[5] The divergence time for the Sami haplogroup V sequences was estimated by Max Ingman and Ulf Gyllensten at 7600 YBP (years before present), and for U5b1b1 as 5500 YBP amongst Sami and 6600 YBP amongst Sami and Finns. This suggests to them an arrival in the region soon after the retreat of the glacial ice.[6]

U5b

Although a small proportion of the Haplogroup U (mtDNA) among the Sami falls into U4, the great majority is U5b. The percentage of total Sami mtDNA samples tested by K. Tambets and her colleagues (published in 2004) which were U5b ranged from 56.8% in Norwegian Sami to 26.5% in Swedish Sami.[5] In research made by M. Ingman and U. Gyllensten in 2006 shows a slightly different setting: Norwegian Sami belongs to U5b as well as U5b1b1 to 56.8%, Finnish Sami with 40.6%, Northern Sami in Sweden to 35.5% and Southern Sami in Sweden within reindeer herding to 23.9% while Southern Sami in Sweden outside of reindeer herding/other occupation belong to U5b to 16.3% and to U5b1b1 to 12%.[7] Sami U5b falls into subclade U5b1b1. The Sami U5b1b1 [5] sub-clade is present in many different populations, e.g. 3% or higher frequencies in Karelia, Finland, and Northern-Russia.[5] The Sami U5b1 motif is additionally found in very low frequencies for instance in the Caucasus region, however this is explained as recent migration from Europe.[8] However 38% of the Sami U5b1b1 mtDNAs have haplotype so far exclusive to the Sami, containing a transition at np 16148.[5]

Alessandro Achilli and colleagues noted that the Sami and the Berbers share U5b1b, which they estimated at 9,000 years old, and argued that this provides evidence for a radiation of the haplogroup from the Franco-Cantabrian refuge area of southwestern Europe.[9]

V

The divergence time for the Sami haplogroup V sequences is estimated by Max Ingman and Ulf Gyllensten at 7.600 years ago. But there is a difference within the Sami group in Sweden according to their study. North Sami (Sami in the North of Swedish Lapland) belong to haplogroup V with 58.6% and South Sami (Sami in the South of Swedish Lapland) within reindeer herding to 37.0% and South Sami outside reindeer herding/other occupation to 8.7%. That can be compared with Sami in Norway that has a 33.1% belonging to haplogroup V and Sami in Finland to 37.7%. Sami in Finland and South Sami in Sweden has the same percentage belonging to haplogroup V.[6] But according to K. Tambets' et al. study is haplogroup V the most frequent haplogroup in the Swedish Sami and is present at significantly lower frequencies in Norwegian and Finnish subpopulations.[5] But as just mentioned, goes those findings against those concluded by Ingman and Gyllensten. What speaks in benefit for Ingman's and Gyllensten's study is that they have deconstructed the Sami investigated in Sweden. That has not been done in the study by K. Tambets et al. A deconstruction of the Sami groups in genetic studies can reveal more closely when that specific group faced immigrants in their areas of habitation.

Torroni and colleagues have suggested that the spread of haplogroup V in Scandinavia and in eastern Europe is due to its late Pleistocene/early Holocene expansion from a Franco-Cantabrian glacial refugium.[10]

However subsequent studies found that haplogroup V is also significantly present in eastern Europeans. Furthermore, haplogroup V lineages with HVS-I transitions 16153 and 16298 that are frequent in the Sami population are much more widespread in eastern than in western Europe. So haplogroup V might have reached Fennoscandia via central/eastern Europe. Such a scenario is indirectly supported by the absence, among the Sami, of the pre-V mtDNAs that are characteristic of southwestern Europeans and northwestern Africans.[5]

Z

Haplogroup Z is found at low frequency in the Sami and Northern Asian populations but is virtually absent in Europe. Several conserved substitutions group the Sami Z lineages with those from Finland and the Volga-Ural region of Russia. The estimated dating of the lineage at 2700 years suggests a small, relatively recent contribution of people from the Volga-Ural region to the Sami population.[6]

Y-DNA

Three Y chromosome haplogroups dominate the distribution among the Sami: N1c (formerly N3a), I1 and R1a at least in the study carried out by K. Tambets et al. in 2004. The most common haplogroup among the Sami is N1c, with I1 as a close second according to that study. Genetics Max Ingman and Ulf Gyllensten came in 2006 to a quite different conclustion in their study from 2006, where the Sami investigated had practically no belonging to that haplogroup I.[4] Haplogroup R1a in Sami is mostly seen in the Swedish Sami and Kola Sami populations, with a low level among the Finnish Sami. Tambets and colleagues suggested that N1c and R1a probably reached Fennoscandia from eastern Europe, where these haplogroups can be found in high frequencies.[5]

However the two haplogroups have a distinctly different linguistic distribution. R1a1a is common among Eastern Europeans speaking Indo-European languages, while N1c correlates closely with the distribution of the Finno Ugrian languages. For example, N1c is common among the Finns, while haplogroup R1a is common among all the neighbours of the Sami.[11] Haplogroup I1 is the most common haplogroup in Sweden, and the Jokkmokk Sami in Sweden have similar structure to Swedes and Finns for haplogroup I1 and N1c. Haplogroup I1a in Sami is explained by immigration (of men) during the 14th century.[12] That is quite late in Sami history bearing in mind that an obvious Sami cultural can be traced and first observed back to 1.000 BC.[13]

Research made in 2006 by Max Ingman and Ulf Gyllensten of Sami in Northern Swedish Lapland (so called North Sami) and Sami in Southern Swedish Lapland (so called South Sami), Sami in Norway and Sami in Finland came to the conclusion that haplogroup I was totally absent in North Sami in Sweden, in Norwegian Sami and Finnish Sami that they had investigated, but existed in South Sami in Sweden to 2.2%. For Sami in Finland and Sami in Norway they had used the study Tambets et al. from 2004 quoated above. But in their own study of Sami in Sweden they separated the group South Sami in Sweden into South Sami within reindeer herding and South Sami outside of reindeer herding/other occupation, and that showed that the former did not belong to haplogrup I but the latter to 3.3%.[14] Through history has Sami areas in Fennoscandinavia faced people moving in, which is the explanation used by Anders O. Karlsson, Thomas Wallerström, Anders Götherström and Gunilla Holmlund from 2006 quoted above.

To foremost Ingman's and Gyllensten's study can be added that former studies showed that the frequency of blood group and protein polymorphisms differ significantly between Sami and the general Swedish population.[15]

See also

References

  1. ↑ L.E. Beckman; K. Sjoberg; S. Eriksson; L. Beckman (2001). "Haemochromatosis gene mutations in Finns, Swedes and Swedish Saamis". Human Heredity. 52 (2): 110–112. doi:10.1159/000053362. PMID 11474212.
  2. ↑ http://www.cell.com/ajhg/abstract/S0002-9297(07)61892-8
  3. ↑ http://www.nature.com/ejhg/journal/v14/n8/full/5201651a.html
  4. 1 2 Ingman, Max; Gyllensten, Ulf (20 September 2006). "A recent genetic link between Sami and the Volga-Ural region of Russia". European Journal of Human Genetics. 15 (1): 115–120. doi:10.1038/sj.ejhg.5201712. ISSN 1018-4813.
  5. 1 2 3 4 5 6 7 8 Kristiina Tambets; Siiri Rootsi; Toomas Kivisild; Hela Help; Piia Serk; et al. (2004). "The Western and Eastern Roots of the Saami—the Story of Genetic "Outliers" Told by Mitochondrial DNA and Y Chromosomes" (PDF). American Journal of Human Genetics. 74: 661–682. doi:10.1086/383203. PMC 1181943. PMID 15024688.
  6. 1 2 3 Max Ingman; Ulf Gyllensten (2007). "A recent genetic link between Sami and the Volga-Ural region of Russia" (PDF). European Journal of Human Genetics. 15 (1): 115–120. doi:10.1038/sj.ejhg.5201712. PMID 16985502.
  7. ↑ http://www.nature.com/ejhg/journal/v15/n1/fig_tab/5201712t1.html#figure-title
  8. ↑ Martin Richards; et al. (2000). "Tracing European Founder Lineages in the Near Eastern mtDNA Pool" (PDF). American Journal of Human Genetics. 67: 1251–1276. doi:10.1016/S0002-9297(07)62954-1. PMC 1288566. PMID 11032788.
  9. ↑ Achilli, Saami and Berbers (2005). "An Unexpected Mitochondrial DNA Link". American Journal of Human Genetics. 76: 883–886. doi:10.1086/430073. PMC 1199377. PMID 15791543.
  10. ↑ A. Torroni; et al. (2001). "A signal, from human mtDNA, of postglacial recolonization in Europe". American Journal of Human Genetics. 69: 884–885. doi:10.1086/323485. PMC 1226069. PMID 11517423.
  11. ↑ Tuuli Lappalainen; Satu Koivumäki; Elina Salmela; Kirsi Huoponen; Pertti Sistonen; Marja-Liisa Savontaus; Päivi Lahermo (2006). "Regional differences among the Finns: A Y-chromosomal perspective". Gene. 376 (2): 207–215. doi:10.1016/j.gene.2006.03.004. PMID 16644145.
  12. ↑ Andreas O Karlsson, ThomasWallerström, Anders Götherström and Gunilla Holmlund (2006). "Y-chromosome diversity in Sweden – A long-time perspective". European Journal of Human Genetics. 14 (8): 963–970. doi:10.1038/sj.ejhg.5201651. PMID 16724001.
  13. ↑ Lars Ivar Hansen & Bjornar Olsen, "Hunters in Transition. An Outline of Early Sámi History (2014) p. 14
  14. ↑ Ingman, Max; Gyllensten, Ulf (2006-09-20). "A recent genetic link between Sami and the Volga-Ural region of Russia". European Journal of Human Genetics. 15 (1): 115–120. doi:10.1038/sj.ejhg.5201712. ISSN 1018-4813.
  15. ↑ Early studies showed that the frequency of blood group and protein polymorphisms differ significantly between Sami and the general Swedish population.
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