Résumé
We know much about pathogen evolution and the emergence of new disease
strains but less about host resistance and how it is signaled to other
individuals and subsequently maintained. The cline in frequency of
black-coated wolves across North America is hypothesized to result from a
relationship with canine distemper virus (CDV) outbreaks. We test this
hypothesis using cross-sectional data from wolf populations across North
America that vary in the prevalence of CDV and the allele that makes coats
black, longitudinal data from Yellowstone National Park, and modeling. The
frequency of CDV outbreaks generates fluctuating selection that results in
heterozygote advantage that in turn impacts the frequency of the black
allele, the optimal mating behavior, and the black wolf cline across the
continent.