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Swedish population substructure revealed by genome-wide single nucleotide polymorphism data
Elina Salmela1, Tuuli Lappalainen, Jianjun Liu
1Institute for Molecular Medicine Finland (FIMM), University of Helsinki, Helsinki, Finland.
Plos One
|February 25, 2011
Summary
Genome-wide SNP data reveals subtle genetic structure within Sweden, with Norrland showing distinct differences. This genetic variation, though minor, is significant for population structure studies and requires careful geographical matching in association studies.
Area of Science:
- Population Genetics
- Human Genomics
- Bioinformatics
Background:
- Genome-wide single nucleotide polymorphism (SNP) data is increasingly valuable for understanding human population structure.
- Previous studies have highlighted the utility of SNP data in population genetics research.
Purpose of the Study:
- To investigate the internal genetic structure of the Swedish population.
- To compare the genetic relatedness of Swedes to other European populations.
Main Methods:
- Genotyping of 1525 Swedes using over 350,000 SNPs on the Illumina HumanHap550 array.
- Comparison with 3212 worldwide reference samples using overlapping SNPs from Illumina and Affymetrix arrays.
Main Results:
- Swedes, particularly from the south, show genetic proximity to Germans and British, with a greater distance to Finns.
- A clinal genetic structure was observed within Sweden, with subtle substructure in southern and middle regions.
- Norrland, in northern Sweden, displayed significant internal genetic differences and distinctiveness from the rest of the country, likely due to isolation and genetic drift.
Conclusions:
- Genome-wide data can reveal substructure in seemingly homogeneous populations like Swedes.
- The observed genetic structure within Sweden, though subtle, may impact the design of genetic association studies, necessitating careful geographical matching of cases and controls.
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