Semester of Graduation

Spring 2024

Degree

Master of Biological Science (MBioSci)

Department

Biological Sciences

Document Type

Thesis

Abstract

The Olympia Oyster is the only native oyster species on the Pacific coast of North America. Seasonality in water temperatures across this threatened species’ broad and fragmented range has been linked to its development, reproductive timing, reproductive activity, growth, and survival rates. Recent evidence suggests parental environments can have carry-over effects on larval growth and respiration rates in response to temperature. In this study, we utilized transcriptomic methods to identify the underlying mechanisms of this cross-generation plasticity. Sequence libraries of adult ctenidia tissue and pooled larval replicates were extracted and spawned from hatchery raised oysters of the same parentage immediately following a 6-month acclimatization experiment at field sites across the Puget Sound Basin. After spawning, larvae from each parental cohort were exposed to two thermal treatments. Using Illumina Tag-seq, we investigated differential gene expression across acclimatization sites, developmental stages, and acute thermal treatments. To further test the association between thermal treatment, quantitative traits, and parental effects, we subjected larval expression data to a signed WGCNA analysis. We identified eigengene modules correlated with larval respiration rates and parental environment. A GO enrichment analysis of modules associated with larval cohorts that had higher growth and respiration at warmer temperatures identified gene ontologies associated with growth and epigenetic mechanisms. We believe this study provides evidence that larvae of O. lurida, a eurythermal marine invertebrate, do not display metabolic stress when exposed to an acute thermal treatment reflecting regional temperatures projected for 2100 (20 ˚C). Moreover, the ability to adjust to sudden temperature changes appears to be conditional with respect to the parental acclimatization site. In conclusion, parental environment has lasting effects on larval acclimation potential, which could have important effects on this species’ ability to respond to climate change.

Date

1-23-2024

Committee Chair

Kelly, Morgan W.

Available for download on Wednesday, January 15, 2025

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