A reassessment of genetic diversity in Icelanders

[Euclides]

Ann Hum Genet. 2003 Jul;67(Pt 4):281-97.


A reassessment of genetic diversity in Icelanders: strong evidence from multiple loci for relative homogeneity caused by genetic drift.

Helgason A, Nicholson G, Stefansson K, Donnelly P.

deCODE Genetics, 101 Reykjavik, Iceland. agnarh@hi.is

There has been some controversy in the literature concerning whether Icelanders are genetically homogenous or heterogeneous relative to other European populations. We reassess this question in the light of large data sets spanning 83 autosomal SNP loci, 14 serogenetic loci, 6622 Y-chromosomes and 3214 sequences from mtDNA hypervariable segments 1 and 2 (HVS1 and HVS2). Our results strongly support the hypothesis that genetic drift, with a consequent loss of variation, has had a greater impact on Icelanders than most other Europeans. We also analyse 7245 HVS1 sequences from 25 European populations. In line with other studies, we observe a deficit of rare HVS1 haplotypes and an excess of intermediate frequency haplotypes in Icelanders compared to most European populations, with some measures of genetic diversity indicating relative heterogeneity and others indicating relative homogeneity of Icelanders. Simulations indicate that genetic drift, and not admixture (as proposed by Arnason, 2003) is the most likely cause of the atypical Icelandic HVS1 frequency spectrum. These simulations reveal that gene diversity (heterozygosity) and mean pairwise differences are largely insensitive to events in recent population history, while statistics based on the number of haplotypes or segregating sites are much more sensitive. Overall, our analyses strongly indicate that the Icelandic gene pool is less heterogeneous than those of most other European populations.

[8Man]

Vikings were in Iceland too, so this may also be of interest:

From the BBC's Viking Genetics Survey Result page:

"The results were interesting. England (and most of mainland Scotland) were a mixture of Angles, Saxons, Danish Vikings and Ancient Britons. The highest percentage of DNA signatures from the invading groups (Angles, Saxons and Danish Vikings) was found in the North and East of England. Interestingly the place with the highest 'invader input' was York, a well-known Viking settlement site.

There was one result in the North and East of England which did not fit this pattern. In Penrith a significant proportion of the men tested had Norwegian DNA signatures on their Y chromosomes. It seems likely that the Norwegian Vikings who travelled along the sea road from Shetland down to the Isle of Man may well have stopped off in Cumbria. It may also have been a safe haven for Vikings expelled from Dublin at the beginning of the 10th century. This finding fits in remarkably well with archaeological finds of Viking burials, Norse-style place- names and stone sculpture. The input of the Angles and Saxons, who arrived in England in the 5th century AD, were represented by DNA samples from Schleswig-Holstein and Northern Saxony respectively."

From: http://www.mirabilis.ca/archives/000058.html