RT Journal Article
SR Electronic
T1 A central role for boom-bust cycles in maintaining genetic variation in fluctuating environments
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 164723
DO 10.1101/164723
A1 Jason Bertram
A1 Joanna Masel
YR 2017
UL http://biorxiv.org/content/early/2017/07/18/164723.abstract
AB The long-running debate about the role of selection in maintaining genetic variation has been given new impetus by the discovery of hundreds of seasonally oscillating polymorphisms in natural Drosophila populations. One possible explanation is that polymorphism is stabilized by an alternating summer-winter selection regime. The general principle that fluctuating environments can promote coexistence is widely accepted, often in the guise of the “storage effect”, yet little has been done to evaluate and compare coexistence mechanisms under seasonally alternating selection coupled with large seasonal variation in population size. Here we distinguish two general mechanisms, which we call “density-regulated growth”, and “protection from selection”. We contrast and compare these mechanisms, both in terms of the underlying biology, and in terms of their capacity to stabilize coexistence. We clarify their connection to the storage effect, which is still sometimes confusingly identified with protection from selection. We also clarify the role of overlapping generations as a form of protection. We find that density-regulated growth is a powerful stabilizer under conditions in which protection from selection might be weak.