RT Journal Article
SR Electronic
T1 A lottery model of density-dependent selection in evolutionary genetics
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 102087
DO 10.1101/102087
A1 J Bertram
A1 J Masel
YR 2017
UL http://biorxiv.org/content/early/2017/05/12/102087.abstract
AB Fitness is typically represented in heavily simplified terms in evolutionary genetics, often using constant selection coefficients, to make it easier to infer or predict how type frequencies change over time. This excludes fundamental ecological factors such as dynamic population size or density-dependence from the most genetically-realistic treatments of evolution, a problem that inspired MacArthur’s influential but problematic r/K theory. Following the spirit of r/K-selection as a general-purpose theory of density-dependent selection, we develop a new model of density-dependent selection by generalizing the fixed-density classic lottery model of territorial acquisition to accommodate arbitrary population densities. We show that, with density dependence, co-existence is possible in the lottery model in a stable environment. Inspired by natural Drosophila populations, we consider co-existence under strong, seasonally-fluctuating selection coupled to large cycles in population density, and show that co-existence (stable polymorphism) is promoted via a combination of the classic storage effect and density-regulated population growth. We also show that the only significant bias introduced by selection at the different environmental extremes of Grime’s triangle is the relative importance of competitive ability at different densities, confirming an important role for phenotypic constraints in shaping “primary strategies”.“…the concept of fitness is probably too complex to allow of a useful mathematical development. Since it enters fundamentally into many population genetics considerations, it is remarkable how little attention has been paid to it.” — Warren J. Ewens, Mathematical Population Genetics I, 2004, pp. 276