The Difference between the Sexes - From Biology to Behaviour

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Nick Barton

IST, Austria

Biography

My early research was on the narrow zones of hybridization that subdivide many populations; this involved work on a variety of species, including grasshoppers, butterflies, and toads. More recently, my research has been mainly theoretical - especially, the effects of selection on multiple genes and on spatially structured populations. Topics include the evolution of complex traits, models of speciation, the evolution of sex and recombination, and the coalescent process. I have co-authored a textbook, Evolution, which aims to combine molecular and organismal aspects of the subject. I worked at the Department of Genetics, University College London (1982-1990), and then at the Institute of Evolutionary Biology, University of Edinburgh (1990-2008). I recently moved to the Institute of Science and Technology in Austria (www.ist.ac.at).

Abstract

Why sex ?

Why should sexual reproduction be so widespread, despite its obvious disadvantages? It is arguable that sex between bacteria is an accidental side-effect of other processes. However, the elaborate cycle of meiosis and sexual union that is part of the life cycle of almost all eukaryotes is an adaptation - most likely, an adaptation for generating variation that will facilitate natural selection. This explanation seems intuitively obvious, yet it has taken several decades for its theoretical basis to become clear. Indeed, we do not yet know what kind of selection is involved (deleterious mutations, adaptive substitution, or coevolution between hosts and pathogen, ...), and we do not understand how this selection can maintain sexual reproduction despite its costs. The recent flood of genomic data may soon resolve these questions.