Population Genetics of the Sami Peoples

Autosomal DNA in Sami Populations

In the early years of genetic research the Sami people caught the scientists interest because of their unusual blood group distribution (Boyd 1939, Mourant 1952, Ryttinger 1957). In later years, the use classic chromosomal marker variation did not enlighten any further the origin of the Sami, extensive Caucasoid and Mongoloid admixture were suggested (Cavelli-Sforza 1994), however not all studies supported the idea of extensive admixture (Beckman 1996, Niskanen 2002). The classical markers genetic distance showed the Sami to have no close relatives in any populations, but a closer affinitity to neightbouring populations (Cavelli-Sforza 1994, Niskanen 2002). The Sami are not more closely related to Siberian and Mongol populations than other European populations, even their Scandinavian neighbours (Niskanen 2002), this in contrast to the historically held view that the Sami are of Siberian-Asiatic origin.

mtDNA Haplogroups in Sami Populations

Overview

As with all other Central and Northern European populations, the mitochondrial (mtDNA) lineage of the indigenous Sami peoples stems largely from a hunter-gatherer population that resided in southwestern Europe during the late Upper Paleolithic (Torroni 1996, Achilli 2004). However, the distribution and frequency of mtDNA haplogroups in Sami populations varies from the distribution patterns of other European and world populations (Tambets 2004).

mtDNA haplogroups V and U (via restricted sequence subsets of its subgroup U5b) represent 89.2% of the averaged total mtDNA haplogroups. mtDNA haplogroup H (which resided in Europe and the Middle East during the Upper Paleolithic) and mtDNA haplogroups D5 and Z (which resided in Asia during the Upper Paleolithic) represent most of the remaining averaged total mtDNA haplogroups. (Local frequencies vary according to region or population.) Of these, the Haplogroups V and U5b have maximums in occurrence in Northern Europe in Sami regions (Tambets 2004).

Restricted mtDNA sequence variations (and subsets in the case of haplogroup U) of wider mitochondrial lineages that stemmed from Southwest Europe and that are today found elsewhere at low and moderate frequencies throughout Europe characterize the strongly outlying nature of the Sami peoples' mtDNA profile and are the result of genetic drift and founder effects (Cavelli-Sforza 1994, Sajantila 1996, Tambets 2004).

mtDNA Haplogroup V

The averaged total of mtDNA haplogroup V in Sami populations overall is ~40% (Meinilä 2001).

Some other populations that share a higher rate of haplogroup V include the Basque (12.4%) and Pasiego people (18.6%) of the Iberian Peninsula, fact|date=June 2008 and fellow Uralic/Finno-Ugric languages speakers, the Mari people of the Volga-Ural region of Russia (10.2%).

The founding motif of haplogroup V is 16298C (Torroni 1996). The next most common haplotype motif (also shared among populations) is 16298C–16153A, which is found in Berbers, Germans, Finns, Volga Finns, and Sami peoples (Torroni 1996). Unlike mtDNA subhaplogroup U5b HVR1 haplotypes in the Sami peoples, most of the mtDNA haplogroup V HVR1 haplotypes are seen in other European populations, as well (Torroni 2001).

Mitochondrial and autosomal DNA findings and the archaeological record indicate that mtDNA haplogroup V, along with its sister mtDNA haplogroup H (both stemmed from mtDNA haplogroup HV), likely expanded from Franco-Cantabria to Central and Northern Europe after the Second Pleniglacial, or about 12,700 to 10,600 B.C.E. (Torroni 1996, Loogväli 2004, Achilli 2004).

Matching coalescence ages and distribution patterns, and indications from the archaeological record, indicate that mtDNA haplogroup V shares a common origin and spread with mtDNA haplogroup H's subgroups H1 and H3. (Today, mtDNA haplogroup V appears widely throughout western Eurasia but at lower rates outside of Sami populations. Obversely, mtDNA haplogroup H is the most common mtDNA haplogroup in western Eurasia, and its subgroups H1 and H3 make up a large percentage of its total distribution.) Such findings regarding mtDNA haplogroups V, H1, and H3 "attest that the Franco-Cantabrian refuge area was indeed the source of late-glacial expansions of hunter-gatherers that repopulated much of Central and Northern Europe from ∼15,000 years ago" (Achilli 2004).

In addition, correlation analysis and variance and haplotype analysis indicate that mtDNA haplogroup U5b (common in Sami peoples, especially in restricted subsets, Finns, and Estonians) (Villems 2002) and y-DNA haplogroup I1a (common in Sami peoples, Finns, Estonians, Swedes, and Norwegians) also expanded alongside mtDNA haplogroup V from southwestern Europe (Rootsi 2004).

Very low sequence variation and the appearance of only the two most common HVS-I sequences in the Sami indicate that haplogroup V admixed recently from another northwestern European population/s and that a pronounced founder event occurred (Torroni 1996). According to branch length calculations, the most recent common ancestor of the Sami peoples' mtDNA haplogroup V sequences is dated at about 5,600 B.C.E. (Ingman 2006).

mtDNA Subhaplogroup U5b

mtDNA subhaplogroup U5b appears at 32% - 52% in Sami populations (depending on population) (Meinilä 2001).

mtDNA haplogroup U was the first modern human mtDNA haplogroup to appear in Europe. Its oldest subgroup, U5, originated ~50,000 B.C.E. (Finnilä 2000)

Almost 50% of subhaplogroup U5's subclade U5b1b1 HVR1 haplotypes are unique to Sami populations and do not occur elsewhere, while most of the haplogroup V HVR1 haplotypes is also seen among other European populations (Torroni 2001). The age of haplogroup U5b1b1 was estimated by Delghandi 1998 using HVR1 haplotypes only to be between 5 500 to 10 500 years old, and by Ingman 2006 using full mtDNA sequences haplogroup U5b1b1 and V was estimated to be 5 500 and 7 500 years old respectively. It is believed on the basis of correlation analysis that haplogroup V and U5b migrated togheter with male haplogroup I1a (Rootsi 2004) and on the basis of variance and haplotype analysis its believed they migrated from western Europe.

The "Sami-specific motif" subset of mtDNA subhaplogroup U5b occurs in 12% of Finns (compared to 34% in Finnish Sami) in Finland's Oulu Province as a result of Sami admixture. (Finns in the more northern Lapland Province were not studied because recent maternal Sami ancestry could not ruled out.) (Meinilä 2001)

yDNA Haplogroups in Sami Populations

Sami Y chromosomes haplogroup distribution is similar to the Finns and Estonians with haplogroup N3, I1a and R1a as major haplogroups (Tambets 2004). Haplogroup I1a is common among all neighbouring populations (Dupuy 2005, Karlsson 2006, Lappalainen 2006, Tambets 2004). Haplogroup N3a is common among the Finns, while haplogroup R1a is common among all the neighbours except the Finns (Lappalainen 2006). Haplogroup R1a in Sami is mostly seen in the Swedish Sami and Kola Sami populations (Tambets 2004). However, an analysis of the microsatellite substructure of haplogroup I1a and N3a among the East Sami reveals that Finns and Estonians are an unlikely source of recent contributions (Raitio 2001), while the Jokkmokk Saami in Sweden have similar structure as among Swedes and Finns for haplogroup I1a and N3 (Karlsson 2006).

ee also

*Basque people#Genetics
*Y-DNA haplogroups by ethnic groups

References

* L. Luca Cavalli-Sforza, Paolo Menozzi, Alberto Piazza 1994: The History and geography of human genes. "Mémoires Princeton, N.J. : Princeton University Press"
* A Sajantila, P Lahermo, T Anttinen, M Lukka, P Sistonen, M L Savontaus, P Aula, L Beckman, L Tranebjaerg, T Gedde-Dahl, L Issel-Tarver, A DiRienzo and S Pääbo 1995: Genes and languages in Europe: an analysis of mitochondrial. "Mémoires Genome Res. 1995 5: 42-52"
* Kristiina Tambets, Siiri Rootsi, Toomas Kivisild, Hela Help, Piia Serk, Eva-Liis Loogväli, Helle-Viivi Tolk, Maere Reidla, Ene Metspalu, Liana Pliss, Oleg Balanovsky, Andrey Pshenichnov, Elena Balanovska, Marina Gubina, Sergey Zhadanov, Ludmila Osipova, Larisa Damba, Mikhail Voevoda, Ildus Kutuev, Marina Bermisheva, Elza Khusnutdinova, Vladislava Gusar, Elena Grechanina, Jüri Parik, Erwan Pennarun, Christelle Richard, Andre Chaventre, Jean-Paul Moisan, Lovorka Barać, Marijana Peričić, Pavao Rudan, Rifat Terzić, Ilia Mikerezi, Astrida Krumina, Viesturs Baumanis, Slawomir Koziel, Olga Rickards, Gian Franco De Stefano, Nicholas Anagnou, Kalliopi I. Pappa, Emmanuel Michalodimitrakis, Vladimir Ferák, Sandor Füredi, Radovan Komel, Lars Beckman, and Richard Villems1 2004: The western and eastern roots of the Saami--the story of genetic "outliers" told by mitochondrial DNA and Y chromosomes.. " Am J Hum Genet. 2004 April; 74(4): 661–682. "
* Beckman, Lars 1996: Samerna, en genetiskt unik urbefolkning : fyra decenniers genetiska studier av svenska samer : från blodgrupper till mitokondriellt DNA . "Umeå : Institutionen för medicinsk genetik, Umeå universitet"
* Lounès Chikhi, Giovanni Destro-Bisol, Giorgio Bertorelle, Vincenzo Pascali, and Guido Barbujani: Clines of nuclear DNA markers suggest a largely Neolithic ancestry of the European gene pool. " Proc Natl Acad Sci U S A. 1998 July 21; 95(15): 9053–9058. "
* Diana Muir Appelbaum and Paul S. Appelbaum. "The Gene Wars," Azure, Winter 5767 / 2007, No. 27 http://www.azure.org.il/magazine/magazine.asp?id=347

External links

* [http://www.promega.com/geneticidproc/ussymp6proc/antti.htm#RESDISC Mitochondrial DNA Diversity in Europe, Sajantila 1995]
* [http://www.genome.org/cgi/reprint/5/1/42 Genes and Languages in Europe: An Analysis of Mitochondrial Lineages, Sajantila 1995]
* [http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=8651309 The genetic relationship between the Finns and the Finnish Saami (Lapps): analysis of nuclear DNA and mtDNA, Lahermo 1996]
* [http://content.karger.com/ProdukteDB/produkte.asp?Aktion=ShowPDF&ProduktNr=224250&ArtikelNr=22789&filename=22789.pdf Saami Mitochondrial DNA Reveals Deep Maternal Lineage Clusters, Delghandi 1998]
* [http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=21201 Clines of nuclear DNA markers suggest a largely Neolithic ancestry of the European gene pool, Chicki 1998]
* [http://www.promega.com/geneticidproc/ussymp6proc/antti.htm#RESDISC Geographic Patterns of mtDNA Diversity in Europe, Simoni 2000]
* [http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=11588400 Evidence for mtDNA admixture between the Finns and the Saami, Meinilä 2001]
* [http://www.genome.org/cgi/content/full/11/3/471 Y-Chromosomal SNPs in Finno-Ugric-Speaking Populations Analyzed by Minisequencing on Microarrays, Raitio 2001]
* [http://www.mankindquarterly.org/samples/niskanenbalticcorrected.pdf The Origin of the Baltic-Finns from the Physical Anthropological Point of View, Niskanen 2002]
* [http://www.journals.uchicago.edu/AJHG/journal/issues/v74n4/40783/40783.web.pdf?erFrom=-5062850973136747401Guest The Western and Eastern Roots of the Saami—the Story of Genetic “Outliers” Told by Mitochondrial DNA and Y Chromosomes, Tambets 2004]
* [http://www.pubmedcentral.nih.gov/picrender.fcgi?artid=1199377&blobtype=pdf Saami and Berbers—An Unexpected Mitochondrial DNA Link, Achilli 2005]
* [http://www.nature.com/ejhg/journal/v15/n1/pdf/5201712a.pdf A recent genetic link between Sami and the Volga-Ural region of Russia, Ingman 2006]