Sexual Dimorphism and Consequences of Sex-Specific Selection in Drosophila melanogaster

Males and females exhibit remarkable phenotypic differences, largely caused by sex-biased geneexpression. Most of this sexual dimorphism is thought to arise because selection favours divergent phenotypes in the sexes. With Drosophila melanogaster as the study organism, my thesis takes several approaches to investigate sexual dimorphism and the implications of sex differences in selection. In Chapter 2, I examined the nature of cis-regulatory variation in connection to sex-biased gene expression. I detected widespread cis-regulatory variation between the study populations, with unbiased genes being marginally enriched for said variation. In numerous genes, cis-regulatory effect on expression differed between the sexes; as expected, such instances of sex-specific cis effects were more prominent in the highly dimorphic gonads than heads. In Chapter 3, I studied gene expression divergence among distinct mating treatments, which had variable consequences for sex-specific selection. Several genes showed divergence among treatments, with sex-biased (especially, male-biased) genes being overrepresented. The direction of divergence among treatments varied with sex-biased gene expression. Significant changes in gene expression dimorphism were also detected among treatments, with the direction of change contingent upon sex-biased gene expression. In Chapter 4, I sought to characterise patterns of genomic divergence among the same treatments as Chapter 3, albeit with a different set of populations. I identified genes with high genomic divergence, but failed to detect any marked relationship with sex-biased gene expression, possibly due to the ubiquity of linkage disequilibrium in the populations. Taken together, my thesis provides further insights into the implications of sex differences in selection, particularly with respect to the evolution of sexual dimorphism.

Department dc:contributor.department

Ecology and Evolutionary Biology

Year dc:date.issued

2024

Author dc:creator

• Mishra, Prashastha

Advisor dc:contributor.advisor

• Agrawal, Aneil F

• Evolutionary genetics
• Gene expression
• Sex-specific selection
• Sexual dimorphism

Statement dc:rights

• Attribution-NonCommercial-ShareAlike 4.0 International

Licence dc:rights.uri

• http://creativecommons.org/licenses/by-nc-sa/4.0/

Handle dc:identifier.uri

http://hdl.handle.net/1807/141177

OAI identifier oai:identifier

oai:utoronto.scholaris.ca:1807/141177