@article{Population:1795,
      recid = {1795},
      author = {Silliman, Katherine Elizabeth},
      title = {Population Structure and Local Adaptation in the Olympia  Oyster (Ostrea lurida)},
      publisher = {The University of Chicago},
      school = {Ph.D.},
      address = {2019-06},
      pages = {126},
      abstract = {Effective management of threatened species requires an  understanding of both the genetic connectivity among  populations and adaptive population divergence. For the  numerous coastal marine species with planktonic dispersal,  high connectivity can obscure population boundaries and  oppose the diversifying effects of natural selection  through homogenizing gene flow. Using an ecologically and  commercially important marine bivalve as a model system, my  dissertation aimed to characterize the spatial scales of  neutral and adaptive differentiation in the face of gene  flow and identify candidate loci under selection. The  Olympia oyster (Ostrea lurida) is native from Baja  California to the central coast of Canada and distributed  over strong environmental gradients. Following devastating  commercial exploitation by the early 20th century, recovery  of O. lurida populations has faced other anthropogenic  challenges, including ocean acidification. For my  dissertation, I used high-throughput sequencing,  bioinformatics, and mesocosm experiments to 1) describe the  neutral and adaptive population genetic structure in O.  lurida, 2) characterize adaptive phenotypic variation at a  local scale, and 3) evaluate molecular responses to  acidification stress across genetically diverged  populations in two bivalve species.

Significant population  structure in the Olympia oyster was observed using both  neutral and putative adaptive genetic markers derived from  genotype-by-sequencing of oysters across 20 sites. To  determine if local adaptation can occur among populations  with high inferred gene flow, I investigated genetic and  phenotypic variation among three populations of oysters in  Puget Sound, WA. Through a common garden experiment on  oysters that had been reared for up to two generations in  common conditions, I demonstrated that these three  populations exhibit heritable differences in reproductive  timing, larval growth rate, and juvenile growth rate.  Adaptations to natural long-standing variation of ocean pH  in widespread species along western North America may be  informative for predicting resilience to projected  conditions. Overlapping the Olympia oyster’s range, the  purple-hinged rock scallop (Crassadoma gigantea) is found  from southern California to the Aleutian Islands. To  understand inter- and intraspecific variation in response  to reduced pH, I compared gene expression responses to two  pH treatments (7.4 and 7.8) in adult oysters and rock  scallops from multiple genetically diverged populations.  Within species, genes were identified that exhibited a  conserved response to pH across populations or a  significant population-specific response—the latter are  considered candidate genes involved in local adaptation.},
      url = {http://knowledge.uchicago.edu/record/1795},
      doi = {https://doi.org/10.6082/uchicago.1795},
}