Fluctuating selection and the determinants of genetic variation

Recent studies of cosmopolitan Drosophila populations have found hundreds to thousands of genetic loci with seasonally fluctuating allele frequencies, bringing temporally fluctuating selection to the forefront of the historical debate surround-ing the maintenance of genetic variation in natural populations. Numerous mech-anisms have been explored in this longstanding area of research, but these exciting empirical findings have prompted several recent theoretical and experi-mental studies that seek to better understand the drivers, dynamics, and ge-nome-wide influence of fluctuating selection. In this review, we evaluate the latest evidence for multilocus fluctuating selection in Drosophila and other taxa, highlighting the role of potential genetic and ecological mechanisms in maintain-ing these loci and their impacts on neutral genetic variation.