Evolutionary relationships of East African soda lake cichlid fish

• Main Author: Ford, A. G. P.
• Published: University College London (University of London) 2015
• Online Access: https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.746026

This thesis examines the evolutionary relationships of the Alcolapia soda lake cichlid fishes of East Africa. The introduction presents background on the soda lakes in which the cichlids are found, the taxonomy and biology of the fishes, as well as the theoretical background to the study. Chapter two discusses the methods used in the thesis, addressing the benefits and limitations of each, as well as their suitability to the study in hand. Chapter three investigates the phylogenetics and phylogeography of soda lake cichlids sampled at several populations around the soda lakes and a single transplanted population outside of the focal lakes, employing a large genomic dataset generated through restriction site associated DNA (RAD) sequencing, and demonstrates low levels of interspecific genomic differentiation with high levels of ongoing gene flow. Chapter four uses the RAD dataset to test for signals of selection between Alcolapia species, employing genome-wide scans and outlier detection to characterise peaks of genomic divergence between species. Chapter five combines morphological (geometric morphometrics) and ecological (stable isotope, stomach contents) data with the RAD dataset from chapter three to consider biologically relevant diversification between Alcolapia species, testing for convergence and niche adaptation. Chapter six examines the ecomorphology of the soda lake fishes at an intraspecific level, testing for effects of geography and environment on morphological differentiation between populations. Finally, chapter seven draws together the conclusions inferred from the thesis, and discusses possible future directions for research in this system.