CDCV

Myles S, Davison D, Barrett J, Stoneking M & Timpson N 2008 Worldwide population differentiation at disease-associated SNPs. BMC Med Genomics 1:22.

• disease SNPs are not significantly more differentiated between populations than random SNPs in the genome
• risk allele frequencies, however, do show substantial variation across human populations and may contribute to differences in disease prevalence between populations
• in some cases, risk allele frequency differences are unusually high compared to random SNPs and may be due to the action of local (i.e. geographically-restricted) positive natural selection
• some risk alleles were absent or fixed in a population
• risk alleles identified in one population do not necessarily account for disease prevalence in all human populations

• several disease-associated SNPs do show evidence of positive local selection
• regardless of whether the observed differences are due to drift or selection, worldwide variation in risk allele frequencies is considerable