Adaptation Genomics of Surfperch Populations in the Context of Rapid Environmental Change

• Main Author: Toy, Jason A.
• Other Authors: Kroeker, Kristy J
• Format: Thesis
• Language: English
• Published: eScholarship, University of California 2022
• Subjects: Ecology; Genetics; Evolution & development; adaptation; evolutionary rescue; local adaptation; molecular ecology; ocean acidification; ocean change; Ocean acidification
• Online Access: https://escholarship.org/uc/item/7z1104s2; https://escholarship.org/content/qt7z1104s2/qt7z1104s2.pdf

While the immediate impacts of global climate change are of serious concern, the outcomes of these environmental changes for populations will ultimately play out over multiple generations. Despite this, our understanding of the evolutionary impacts of climate-related environmental change is still in its early stages, particularly in the marine realm. Furthermore, evolutionary processes can act over short, ecological timescales, such that they may play a key role in both the short-term resistance and long-term resilience of natural populations. Therefore, the objective of this dissertation is to better incorporate evolutionary processes into the developing understanding of the ecological effects of global change. In particular, I focus my investigations on the relationships between genetic diversity, local adaptation, and environmental change to better understand the evolutionary factors that contribute to a population’s adaptive capacity and resilience. A population’s genetic diversity may translate to response (phenotypic) diversity, the level of which will determine the likelihood of evolutionary rescue via the portfolio effect. Adaptation of subpopulations to their local conditions (local adaptation) has the potential to enhance broad-scale genetic diversity within a species, potentially increasing resilience in the face of environmental change, but can simultaneously reduce local diversity, increasing the risk of extinction for subpopulations if gene flow is low. In this dissertation, I use a pair of marine fish species with unique life-histories (Embiotoca jacksoni and Brachyistius frenatus; family Embiotocidae) to 1) test the molecular impact of environmental change on an important temperate fish group, 2) investigate the scale of genetic diversity and admixture along the Pacific coast of North America, 3) provide evidence of local adaptation among subpopulations, and 4) associate genomic differences between subpopulations with regional environmental differences to better understand the physiological ...