Postdoctoral Fellowship: OCE-PRF: The genetic basis of disease resistance in the critically endangered black abalone (Haliotis cracherodii)

University Of California-Santa Cruz, Santa Cruz CA

Investigators

Abstract

The black abalone is a large shelled mollusk found in rocky tidal areas along the California coast. These animals have long been a prized food source for humans, and the shells have served many cultural roles for both early and modern humans in California. The species is now near extinction due to a combination of overfishing and the recent spread of a devastating disease – ‘withering syndrome’ – that has reduced populations by as much as 99%. Recent work has shown that surviving populations exhibit some resistance to the disease, but the mechanism of this resistance and how it relates to the local environment is poorly understood. This project aims to use ancient shells and modern abalone to identify the genetic basis of resistance to withering syndrome. The results of this research can guide the survival and recovery of this valued species. Regular communication with state and federal fisheries managers will inform conservation efforts. The project will support public engagement through the University of California Santa Cruz's (UCSC) Seymour Marine Discovery Center and the Indigenous Communities involved with abalone shell archaeology. The research will also provide multiple types of training opportunities for students at UCSC, which is a Hispanic-Serving Institution. This project aims to understand the genetic basis of adaptation to withering syndrome through the lens of black abalone biology, population history, and local environmental variation. Extreme natural selection events can result in rapid evolution occurring on observable time scales. In historically large panmictic populations like the black abalone – and many other marine organisms – it is unclear how this adaptive process will proceed, especially against a backdrop of fisheries- mediated decline and spatially variable selection. This research will contribute substantially to our understanding of this process by examining how, at the population genomic level, black abalone have changed in response to the rapid spread of withering syndrome. The project has three primary objectives: 1) Use ancient DNA obtained from abalone shells to identify genetic loci under selection in response to withering syndrome; 2) Apply transcriptomic analyses to populations across the species’ range to home in on selected loci associated with changes in gene expression and local environment; and 3) Assay the performance of live abalone in a common garden setting testing whether different genotypes at loci under selection are contributing to local adaptation in today’s populations. Altogether, the resources and results generated by this project will address key questions about the genetics of adaptation in marine organisms. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.