Download Relatedness and Differential Disease Expression in Abalone (G

Relatedness and Differential Disease Expression in Abalone (Genus Haliotis)
M. Harits Abdurrohman
Mentors: Alyssa R. Frederick, Donovan P. German
Abalone were once abundant along the shores of the northeast Pacific Ocean, supported a huge commercial
harvest along the California coast, and were crucial in maintaining kelp forest ecosystems. However, in 1982,
El Niño-Southern Oscillation led to the catastrophic decline of several species of abalone. The culprit for this
demise was a newly observed bacteria (Candidatus Xenohaliotis californiensis), which leads to changes in the
digestive tract that leave abalone without the ability to digest and absorb nutrients, a disease called withering
syndrome (WS). Interestingly, Candidatus X. californiensis has been documented in most abalone species, but,
WS only manifests in a small proportion of abalone species at environmentally relevant temperatures. These
inherent differences in resistance to WS led to the objective of this project - to create a robust phylogeny for
California abalone and map WS tolerance on that tree to better understand why some species are more
susceptible to WS. We extracted the DNA from preserved foot muscle tissues of Californian abalone and
amplified 698 bp of the cytb gene, 342 bp of the h3 gene, and 520 bp of the 16s gene by PCR. The genes were
aligned using CodonCode, and Bayesian analysis was completed with MrBayes (v3.2.6). The results show that
highly resistant species of abalone (Haliotis corrugata and H. fulgens) form their own monophyletic clade,
suggesting that an ancestor of these two species may have evolved a unique mechanism for WS resistance.