ANTAGONISTIC VERSUS NONANTAGONISTIC MODELS OF BALANCING SELECTION: CHARACTERIZING THE RELATIVE TIMESCALES AND HITCHHIKING EFFECTS OF PARTIAL SELECTIVE SWEEPS
Article first published online: 27 SEP 2012
© 2012 The Author(s). Evolution© 2012 The Society for the Study of Evolution.
Volume 67, Issue 3, pages 908–917, March 2013
How to Cite
Connallon, T. and Clark, A. G. (2013), ANTAGONISTIC VERSUS NONANTAGONISTIC MODELS OF BALANCING SELECTION: CHARACTERIZING THE RELATIVE TIMESCALES AND HITCHHIKING EFFECTS OF PARTIAL SELECTIVE SWEEPS. Evolution, 67: 908–917. doi: 10.1111/j.1558-5646.2012.01800.x
- Issue published online: 5 MAR 2013
- Article first published online: 27 SEP 2012
- Accepted manuscript online: 8 SEP 2012 12:00PM EST
- Received May 30, 2012, Accepted August 19, 2012
- genetic variation;
- sex linkage;
- sexual conflict
Antagonistically selected alleles-–those with opposing fitness effects between sexes, environments, or fitness components-–represent an important component of additive genetic variance in fitness-related traits, with stably balanced polymorphisms often hypothesized to contribute to observed quantitative genetic variation. Balancing selection hypotheses imply that intermediate-frequency alleles disproportionately contribute to genetic variance of life-history traits and fitness. Such alleles may also associate with population genetic footprints of recent selection, including reduced genetic diversity and inflated linkage disequilibrium at linked, neutral sites. Here, we compare the evolutionary dynamics of different balancing selection models, and characterize the evolutionary timescale and hitchhiking effects of partial selective sweeps generated under antagonistic versus nonantagonistic (e.g., overdominant and frequency-dependent selection) processes. We show that the evolutionary timescales of partial sweeps tend to be much longer, and hitchhiking effects are drastically weaker, under scenarios of antagonistic selection. These results predict an interesting mismatch between molecular population genetic and quantitative genetic patterns of variation. Balanced, antagonistically selected alleles are expected to contribute more to additive genetic variance for fitness than alleles maintained by classic, nonantagonistic mechanisms. Nevertheless, classical mechanisms of balancing selection are much more likely to generate strong population genetic signatures of recent balancing selection.