Presentation Title

Genetic Barcode Analysis of Octocoral Communities in the Indo-Pacific

Faculty Mentor

Catherine McFadden, Andrea Quattrini

Start Date

23-11-2019 10:45 AM

End Date

23-11-2019 11:30 AM

Location

52

Session

poster 4

Type of Presentation

Poster

Subject Area

biological_agricultural_sciences

Abstract

Octocorallia (soft corals and sea fans) frequently lack diagnostic morphological characteristics, making identification of species for the purposes of conservation or taxonomy unreliable. Studies among the diverse communities in the Indo-Pacific have suggested that genetic barcoding is a promising method of species delimitation of octocorals. Due to the slow evolution of corals and the lack of a barcoding gap, multiple loci are needed, but a combination of 2-3 loci has been used to sort unknown specimens with approximately 70% accuracy when compared to identification by a taxonomic expert In this study, two pairs of three loci – mtMutS, COI, and 28S – were used to group genetically similar specimens into molecular operational taxonomic units ( MOTUs) from three locations throughout the Indo-Pacific. MOTUs were compared between locations, and shared MOTUs were used to determine genetic similarity of communities and as a proxy for species in other analyses. Three sites analyzed in this study (Reunion I.; Kenting, Taiwan; Ryukyu Is., Japan) were compared to several reference sites in the Indo-Pacific. Reunion was expected to be most similar to Madagascar, but Madagascar and Israel were more similar than the former pair. Kenting was not very similar to any of the Taiwanese reference sites, but the Ryukyus were. This all suggests that physical proximity alone is not a predictor of genetic similarities.

In parallel to the genetics studies, the morphology of the Ryukyu samples was assessed with the hopes of finding some diagnostic characteristics for specific MOTUs (which were here being used as a proxy for species). Many species that shared similar characteristics were found to be phylogenetically distant, suggesting that, while further analysis is needed, barcoding is an effective method of species delimitation.

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Nov 23rd, 10:45 AM Nov 23rd, 11:30 AM

Genetic Barcode Analysis of Octocoral Communities in the Indo-Pacific

52

Octocorallia (soft corals and sea fans) frequently lack diagnostic morphological characteristics, making identification of species for the purposes of conservation or taxonomy unreliable. Studies among the diverse communities in the Indo-Pacific have suggested that genetic barcoding is a promising method of species delimitation of octocorals. Due to the slow evolution of corals and the lack of a barcoding gap, multiple loci are needed, but a combination of 2-3 loci has been used to sort unknown specimens with approximately 70% accuracy when compared to identification by a taxonomic expert In this study, two pairs of three loci – mtMutS, COI, and 28S – were used to group genetically similar specimens into molecular operational taxonomic units ( MOTUs) from three locations throughout the Indo-Pacific. MOTUs were compared between locations, and shared MOTUs were used to determine genetic similarity of communities and as a proxy for species in other analyses. Three sites analyzed in this study (Reunion I.; Kenting, Taiwan; Ryukyu Is., Japan) were compared to several reference sites in the Indo-Pacific. Reunion was expected to be most similar to Madagascar, but Madagascar and Israel were more similar than the former pair. Kenting was not very similar to any of the Taiwanese reference sites, but the Ryukyus were. This all suggests that physical proximity alone is not a predictor of genetic similarities.

In parallel to the genetics studies, the morphology of the Ryukyu samples was assessed with the hopes of finding some diagnostic characteristics for specific MOTUs (which were here being used as a proxy for species). Many species that shared similar characteristics were found to be phylogenetically distant, suggesting that, while further analysis is needed, barcoding is an effective method of species delimitation.