Plague-driven selection enriched familial Mediterranean fever mutations in Armenia

Abstract

The discovery that positive selection due to resistance to malarial infection maintained the prevalence of sickle cell and other disease alleles was a landmark in evolution, genetics and epidemiology. Mutations in the MEFV gene causing familial Mediterranean fever with high frequency in Eastern Mediterranean populations give the only other strong candidates for a similar process. Here we estimate a pathogenic MEFV mutation burden in Armenians with a carrier rate of ~41%: a worldwide maximum. By combining these data with regional ancient MEFV genotypes spanning more than 60 centuries, we establish that the allele frequencies of three mutations M694V, M680I, and V726A underwent recent rapid increases, indicating positive selection with an onset consistent with the first Yersinia pestis plague pandemic, ~541 CE to 767 CE or even earlier in time, echoing functional data implying resistance to this infection as the selective agent. This extends to three the number of MEFV variants for which there is evidence for strong concurrent selection at this locus in the Eastern Mediterranean, making it unlikely that this geographic peak resulted from chance alone. Although bubonic plague was extremely widespread, the restricted geography of this selection points toward the Eastern Mediterranean as a longstanding enzootic centre with continuous recycling of outbreaks.