POPULATION GENOMICS OF THE GALAPAGOS ISLAND MOCKINGBIRDS AND IMPLICATION FOR CONSERVATION
Date
2023-05-18
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
ORCID
0000-0003-1497-356X
Type
Thesis
Degree Level
Doctoral
Abstract
Islands are considered as natural laboratories for the understanding of the evolutionary process of speciation. The very first muses of Darwin’s insights into evolution by natural selection were the Galapagos mockingbirds (Mimus spp.), a monophyletic group of four endemic species. Three species are restricted to a single island each whereas the fourth species occurs on (almost) all the other islands of the archipelago. These birds, known for their limited long-distance flying capabilities, are considered terrestrial species and serve as a clear example of allopatric evolution occurring on islands. The aim of my PhD research has been to unveil the evolutionary history of the Galapagos mockingbird species and its conservation implications using a whole-genome approach. Therefore, my research focused on generating a de novo reference genome within this monophyletic group in order to establish an adequate framework for subsequent genome-wide analyses (Chapter 2), and with it unveil the natural history of contrasting Galapagos mockingbird populations along the archipelago (Chapter 3). My findings have revealed that after the common ancestor of these species diverged, there was a systematic and directional spread of these species to the islands, which is directly related to the age of the islands. The geological history of the islands and anthropogenic factors have had different impacts on the demography and genetic variability of these species. Typically, smaller populations are more inbred and have higher rates of non-synonymous mutations becoming fixed. However, despite their extremely small sizes, the populations on Darwin, Wolf, and Floreana islands have maintained stable population sizes over many generations, indicating that the accumulation of these mutations has not had any impact on the fitness of these populations.
Description
Keywords
Genomics, Galapagos Islands, Mockingbirds, Ecology, Evolution, Conservation, Island Biogeography, Population Genomics, Mimus
Citation
Degree
Doctor of Philosophy (Ph.D.)
Department
Biology
Program
Biology