Seminar Abstract

Friday, August 01, 2008 • 12:15 PM • Robert N. Noyce Conference Room, SFI

Arthur Robson Department of Economics, Simon Fraser University

Behavior Discussion Group - Testing Theories of Sex against the Observation that Sex is Biparental

Understanding the purpose of sex remains one of the most important unresolved problems in evolutionary biology. Two leading theories of sex are the mutational deterministic hypothesis that sex reduces mutational load, and the Red Queen hypothesis that sex permits a host organism to maintain parity in a never-ending conflict with parasites. These theories have been difficult to distinguish. We propose to distinguish between them by asking if either is consistent with the fact that sexually produced offspring have only two parents, not three or more. It is shown that the mutational deterministic hypothesis implies that a suitable triparental system dominates biparental sex, so the latter should never be observed, contrary to fact. In contrast, it is shown within a highly stylized model that the Red Queen hypothesis can potentially explain biparental sex without conferring an additional advantage to triparental sex.

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