DescriptionLinkage disequilibrium's contribution to the maintenance of sexual reproduction Though sexual reproduction is nearly ubiquitous in nature, its costs are substantial. Foremost among these costs are the twofold cost of males and the cost of destroying successful genetic associations. Understanding the paradox of the persistence of sex despite these detriments is a central question in evolutionary theory. In order to persist regardless of these disadvantages, the benefits of sexual reproduction must be substantial - offspring of sexual reproduction must have at least twice the fitness of asexual clones. The most generalizable hypotheses addressing the benefits of sex propose that genetic drift increases linkage disequilibrium, creating a surfeit of genomes with intermediate fitness. Sexual recombination eliminates linkage disequilibrium, thereby increasing genetic variation for fitness and improving the efficiency of natural selection. However, previous research using this framework has failed to address the biological reality of interactions between genes. Because the cost of destroying beneficial genetic interactions is one of the major costs of sex, this cannot be overlooked. In this work, I use a computational gene network model in which genes interact and genetic interactions evolve to investigate the hypothesis that linkage disequilibrium decreases the fitness and adaptability of asexual populations. I test this both by evolving artificial organisms in conditions that will increase linkage disequilibrium, and by evolving them in an environment with a shifting optimum, which will make linkage disequilibrium more costly. I am running a python script that runs populations of artificial gene networks (numerical matrices) through repeated rounds (on the order of 10s of thousands) of mutation, selection and reproduction, analyzing the evolutionary dynamics of these populations, and storing the data generated by this in text files.
OrganizationUniversity of North Carolina at Chapel Hill
Sponsor Campus GridOSG Connect
Principal Investigator
Christina Burch
Field Of ScienceEvolutionary Sciences