The conditional ancestral selection graph with strong balancing selection.
Using a heuristic separation-of-time-scales argument, we describe the behavior of the conditional ancestral selection graph with very strong balancing selection between a pair of alleles. In the limit as the strength of selection tends to infinity, we find that the ancestral process converges to a neutral structured coalescent, with two subpopulations representing the two alleles and mutation playing the role of migration. This agrees with a previous result of Kaplan et al., obtained using a different approach. We present the results of computer simulations to support our heuristic mathematical results. We also present a more rigorous demonstration that the neutral conditional ancestral process converges to the Kingman coalescent in the limit as the mutation rate tends to infinity.
Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA. wakeley@fas.harvard.edu
John
J
Wakeley
Ori
O
Sargsyan
D000483:Alleles; D003198:Computer Simulation; D008962:Models, Theoretical; D012641:Selection, Genetic