Genetic structure of the Crown-of-Thorns seastar in the Pacific Ocean, with focus on Guam
- Published
- Accepted
- Subject Areas
- Biogeography, Evolutionary Studies, Marine Biology
- Keywords
- Acanthaster ‘planci’, microsatellites, Pacific, COTS, genetic structure, crown-of-thorns seastar
- Copyright
- © 2016 Tusso et al.
- Licence
- This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, reproduction and adaptation in any medium and for any purpose provided that it is properly attributed. For attribution, the original author(s), title, publication source (PeerJ Preprints) and either DOI or URL of the article must be cited.
- Cite this article
- 2016. Genetic structure of the Crown-of-Thorns seastar in the Pacific Ocean, with focus on Guam. PeerJ Preprints 4:e1167v3 https://doi.org/10.7287/peerj.preprints.1167v3
Abstract
Population outbreaks of the corallivorous crown-of-thorns seastar (COTS), Acanthaster ‘planci’ L., are among the most important biological disturbances of tropical coral reefs. Over the past 50 years, several devastating outbreaks have been documented around Guam, an island in the western Pacific Ocean. Previous analyses have shown that in the Pacific Ocean, COTS larval dispersal may be geographically restricted to certain regions. Here, we assess the genetic structure of Pacific COTS populations and compared samples from around Guam with a number of distant localities in the Pacific Ocean, and focused on determining the degree of genetic structure among populations previously considered to be isolated. Using microsatellites, we document substantial genetic structure between 14 localities from different geographical regions in the Pacific Ocean. Populations from the 14 locations sampled were found to be structured in three significantly differentiated groups: (1) all locations immediately around Guam, as well as Kingman Reef and Swains Island; (2) Japan, Philippines, GBR and Vanuatu; and (3) Johnston Atoll, which was significantly different from all other localities. The most stark divergence of these groupings from previous studies is the lack of genetic differentiation between Guam and extremely distant populations from Kingman Reef and Swains Island. These findings suggest potential long-range dispersal of COTS in the Pacific, and highlight the importance of ecological determinants in shaping genetic structure.
Author Comment
This version has been modified after peer review.
Supplemental Information
Predicted allelic richness in function of sample size
Predicted allelic richness in function of sample size. Each line represents sampled localities. Localities with the lowest and highest allelic richness are shown in red and blue respectively, with their variance in dash lines.
Results of the discriminant analysis of principal components (DAPC)
Results of the discriminant analysis of principal components (DAPC). Values of the Bayesian Information Criteria (BIC) in function of number of clusters.
Genetic diversity estimates for 10 microsatellite loci all the localities
Genetic diversity estimates for 10 microsatellite loci all the localities. N number of individuals, Na number of allele per locus, Ar allelic richness, Ho observed heterozygosity, He expected heterozygosity, FIS inbreeding coefficient.
Pairwise Fst bootstrap
Pairwise Fst bootstrap. CI: confidence intervals. BC: Bonferroni correction.