Connecting Genotype and Phenotype: Investigating the Functional Morphology and Molecular Architecture that Influences Craniofacial Divergence Using Lake Malawi Cichlid Fishes

Author

Leah DeLorenzoFollow

Date of Award

5-2024

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Biological Sciences

Committee Chair/Advisor

Dr. Kara Powder

Committee Member

Dr. Richard Blob

Committee Member

Dr. James Lewis

Committee Member

Dr. Christopher Parkinson

Committee Member

Dr. Matthew Turnbull

Abstract

Connecting genotype and phenotype to better understand how species evolve has been a goal of evolutionary developmental biologists over the last 50 years. This dissertation aims to connect genotype and phenotype of the craniofacial skeleton within the adaptive radiation of Lake Malawi cichlids to fortify our understanding of the functional, genetic, and epigenetic factors that contribute to craniofacial divergence. I start with a functional approach using 2D geometric morphometrics to assess craniofacial shape across the Lake Malawi cichlid radiation to bolster our knowledge of the bone phenotypes that are important to niche specialization and are functionally relevant. Next, I use Quantitative Trait Loci (QTL) analyses to determine candidate genes that contribute to feeding performance and ventral craniofacial diversification. Lastly, I investigate the role of epigenetic regulation of chromatin in contributing to craniofacial divergence. I uncover that modulating acetylation during early craniofacial development has time- and species-specific effects on craniofacial morphology. I then used bulk ATAC-seq and RNA-seq on craniofacial tissue of three species of cichlids with distinct craniofacial phenotypes at a developmentally relevant timepoint. I identified differences in the accessibility and expression of genes involved in craniofacial and bone development between our species comparisons signifying the importance of epigenetic regulation in morphological diversification. Together, this research builds on our knowledge of the functional relevance of adaptive morphology and elucidates underlying molecular architecture that contribute to the evolution of craniofacial phenotypes.

Recommended Citation

DeLorenzo, Leah, "Connecting Genotype and Phenotype: Investigating the Functional Morphology and Molecular Architecture that Influences Craniofacial Divergence Using Lake Malawi Cichlid Fishes" (2024). All Dissertations. 3651.
https://open.clemson.edu/all_dissertations/3651

Author ORCID Identifier

0000-0002-0789-8875