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Cambridge NERC Doctoral Training Partnerships

Graduate Research Opportunities

Lead supervisor: Emilia Santos, Zoology

Co-supervisor: Richard Durbin, Genetics; Judith Mank, University of British Columbia

Brief summary: 
Using population genomics, regulatory genomics and genome wide association studies, we will identify and characterise loci associated with sexual dimorphism and sexual conflict in the cichlid species A. calliptera, and determine how such conflict signatures influence male ornament variation and adaptation to the surrounding environments.
Importance of the area of research concerned: 
Sexual selection plays a profound role in the process of adaptation, giving rise to extraordinary sexually dimorphic traits observed in various species. These traits represent some of the most remarkable within-species variation and arise from a genome that is largely shared between males and females. Conflicts between sexes can arise due to divergent reproductive fitness or survival optima for each sex and have profound implications for genome and trait evolution. For instance, alleles that may confer reproductive fitness advantages to one sex (e.g., male nuptial colouration) may be detrimental for the other (e.g., increased predation for females). In such cases, selection acts in opposing directions on the sexes, a situation referred to as sexual conflict or sexual antagonism. There is much debate as to how sexual conflict affects adaptive potential. Such conflict can influence the ability of populations to adapt towards optimal trait values hindering adaptation. However, it has also been hypothesised that it can contribute to an increase or maintenance of genetic and phenotypic variation through balancing selection thereby enhancing adaptive capacity in an ever-changing world.
Project summary : 
Understanding the genetic and ecological basis of sexual conflict is crucial to elucidate its contribution to adaptive trait evolution and the potential constraints it imposes on populations. Yet, the mechanisms by which a shared genome encodes substantially distinct sexual phenotypes remain largely unexplored. Further, only a limited number of sexually antagonistic alleles have been identified, in large part because doing so requires understanding fitness costs and benefits in both sexes. The work proposed in this application directly addresses these issues and is based on our unexpected and preliminary identification of sexually antagonistic variation at a gene that is also involved in male ornament development - eggspots - in the cichlid fish Astatotilapia calliptera.
What will the student do?: 
We will build on these preliminary findings to understand the interplay between sexual dimorphic development, sexual conflict and the evolution of variation in sexually selected male ornaments. More specifically, we set the following questions and specific aims: 1) How does a shared genome encode distinct sexual phenotypes? a. Uncover how sex-specific gene regulatory networks diverge during male and female development. 2) What are the genomic and ecological signatures of sexual conflict and do they contribute to the maintenance of male ornament variation? a. Identify the genomic and ecological basis of sexual conflict. b. Determine if sexual conflict contributes to the maintenance of genetics and phenotypic variation in male ornaments. Taken together, we propose an integrative approach that aims at understanding the impacts of sexual conflict on sexual dimorphic development and male ornament evolution. As such, this research will have a profound impact on our understanding of the mechanisms underlying organismal diversity and the broad field of evolutionary biology.
References - references should provide further reading about the project: 
J. E. Mank, Nat. Ecol. Evol. 1, 1–7 (2017);
R. B. Roberts, J. R. Ser, T. D. Kocher, Science. 326, 998–1001 (2009);
B. Clark, A. Hickey, B. Fischer, J. Elkin, M. E. Santos, bioRxiv (2023);
You can find out about applying for this project on the Department of Zoology page.