1Department of Anthropology, University of Oklahoma, 2Department of Anthropology, University of Louisville
Thursday All day, Park Concourse
The apolipoprotein E (APOE) locus with its associated protein product is involved in multiple metabolic pathways. There is evidence that the three most common alleles—ε2, ε3, and ε4 (ancestral)—confer differential risk for specific chronic disorders including Alzheimer's, atherosclerosis, and hyperlipoproteinemia. APOE allele frequencies are variable among global populations, and it has been argued that diversity at this locus is shaped by natural selection. Less well documented are the effects of relatively recent demographic events, such as genetic bottlenecks, on APOE allele frequencies. This study set out to document APOE frequencies in Scandinavia, as well as populations of the North Atlantic which are characterized by relatively recent population migrations, founder effects, and isolation.
Samples from seven populations—Norway, Sweden, Iceland, Denmark, Ireland, the Shetland Islands, and the Isle of Man—totaling 210 individuals were scored for APOE genotype. Taken as a whole, genotype frequencies among the populations are concordant with other northern but not southern European populations. Within population variation, however, is dependent on location. While continental populations are consistent with regional frequencies, island populations—Iceland, the Isle of Man, and the Shetland Islands—have much higher proportions of ε3/ε3, the highest of which can be found in the Shetland Islands (81%). Additionally, relatively rare genotypes such as ε3/ε2 are found at higher than expected frequencies among island populations. These results document that while allele frequencies at the APOE locus are predictable at a regional level, sub–structuring of local frequencies can vary significantly.