Dr. Charles Mullon

PhD Title:
Investigating the evolution of sex-specific phenotypes

PhD Abstract:
This thesis uses theoretical models to investigate a diverse set of questions that revolve around the evolution sex-specific phenotypes. Chapter 1 studies the evolution of sex-determining mechanisms. It investigates the evolutionary change in the coding sequences of sex determining genes associated with the recruitment of a top regulatory gene in Drosophila. We find that this recruitment coincided with changes in the evolution of all the genes of the sex determining pathway. We discuss how these changes are tied with the genes' molecular functions, and highlight the limits of inference from DNA sequence change only. Chapter 2 investigates the genomic distribution of sexually antagonistic alleles. Our study predicts that the interplay of sexually antagonistic selection and genetic drift leads to the accumulation of sexually antagonistic alleles on the X in XY species and, on the autosomes in ZW species, especially when sexual competition is strong among males. Chapter 3 studies the evolution and consequences of sex-specific reproductive variance by constructing a population genetic model that is based on an explicit representation of sexual reproduction. In particular, we derive the probability of fixation for mutations affecting male and female reproductive traits in different ways and find that sex-specific reproductive variance may have profound consequences for the evolution of sex-specific phenotypes. Finally, chapter 4 adapts this latter model to investigate the evolution of developmental instability in the presence of female choice. Developmental instability can be selected for by female choice. But it can have very dire consequences for other aspects of the phenotype, notably in female fecundity and offspring survival. We discuss the effects of reproductive variance on whether these detrimental effects are capable of preventing developmental instability. Overall, this thesis highlights how not only sex-specific selection, but also sex-specific variance in gene transmission contribute to variation in sex-specific phenotypes.

Current Employment: Post-Doc at the University of Lausanne, Switzerland

Contact: dlm.charles@gmail.com

Relevant Publications:

  • Mullon, C., Pomiankowski, A., & Reuter, M. (2012). Molecular evolution of Drosophila Sex-lethal and related sex determining genes. BMC Evolutionary Biology, 12(1), 5. | Access here |
  • Mullon, C., Pomiankowski, A., & Reuter, M. (2012).The effects of selection and genetic drift on the genomic distribution of sexually antagonistic alleles. Evolution. | Access here |
Charles Mullon

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