OPUS: CRS: Through the looking glass: host-parasite coevolution and genetic recombination

Indiana University, Bloomington IN

Investigators

Abstract

As we look around us, species with both males and females are the general rule. Yet, the persistence of males and females along with reproduction that involves genetic recombination, is a classic problem in biology. The problem stems from the basic fact that males do not give birth. Thus, an all-female lineage that reproduces by simply replicating the adult female (cloning) would be expected to produce twice as many offspring as a population with both males and females. This mode of reproduction should lead to the very rapid spread of the clonal form in populations. But, in spite of this reproductive advantage, clonal reproduction is rare. This paradox dates back to Charles Darwin, and dozens of hypotheses for the advantages of genetic recombination have been put forward. One of the leading hypotheses is the Red Queen, which posits that recombining offspring are favored, on average, because genetically diverse offspring would be more likely to escape rapidly evolving parasites. The goal of this project is to synthesize more than thirty years of work on the Red Queen hypothesis. The synthesis would be published as a book targeting advanced undergraduates and graduate students in biology, would be of interest to the general public. The project also involves the training of secondary school teachers and the continued development of card games to teach high school and college students about evolution. The model organism for this work is a New Zealand freshwater snail (Potamopyrgus antipodarum) in which females that produced recombined offspring and those that only produce clonal offspring coexist. The book would synthesize long-term field observations along with shorter term experiments designed to determine the cost and benefits of producing genetically variable, cross-fertilized offspring. The book would also synthesize theoretical studies of the Red Queen hypothesis; and it would cover some of the key concepts in evolutionary biology, such as hard versus soft selection, frequency-dependent selection, bet-hedging, mutation accumulation, stable equilibria versus oscillatory dynamics, and mate choice. The book would also lay out the fundamentals regarding the ecology and genetics of infectious disease. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.