Genomic Evidence of Rapid and Stable Adaptive Oscillations over Seasonal Time Scales in Drosophila

In many species, genomic data have revealed pervasive adaptive evolution indicated by the fixation of beneficial alleles. However, when selection pressures are highly variable along a species' range or through time adaptive alleles may persist at intermediate frequencies for long periods. So called "balanced polymorphisms" have long been understood to be an important component of standing genetic variation, yet direct evidence of the strength of balancing selection and the stability and prevalence of balanced polymorphisms has remained elusive. We hypothesized that environmental fluctuations among seasons in a North American orchard would impose temporally variable selection on Drosophila melanogaster that…

• NS
  National Science Foundation

  Awards: NSF DEB 0921307, DGE-0822, 0921307
• NI
  National Institutes of Health

  Awards: RO1GM097415, RO1GM100366
• DO
  Division of Environmental Biology

  Award: 0921307