2017 Fiscal Year Annual Research Report
Connectivity and phylogeography of Galaxea (Scleractinia) in the Indo-Pacific
| Project/Area Number |
17J00366
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| Research Institution | Okinawa Institute of Science and Technology Graduate University |
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Principal Investigator |
鈴木 パトリシア姫香 沖縄科学技術大学院大学, 科学技術研究科, 特別研究員(DC2)
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| Project Period (FY) |
2017-04-26 – 2019-03-31
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| Keywords | Galaxea / coral / connectivity / Ogasawara / Symbiodinium / Okinawa / Daito / RAD sequencing |
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| Outline of Annual Research Achievements |
Analysis of Symbiodinium diversity in Galaxea fascicularis was conducted from six different locations in the Ryukyu Archipelago. 67 coral colonies were metabarcoded in the ITS2 region of Symbiodinium using Illumina MiSeq. The variation in community composition among host characteristics, environmental and space were analyzed with Joint Distribution Models. I found no difference between host lineages and temperature but variation according to water depth, host polyp size and bleaching status. Most variation was residual, potentially indicating non-random Symbiodinium community assembly processes in hospite. A manuscript 'the metacommunity ecology of coral-hosted symbionts' is in preparation.
Connectivity in Galaxea fascicularis lineage L between Okinawa, Daito and Ogasawara islands was assessed based on 170 samples. All samples were genomically characterized by restriction site-associated DNA (RAD) sequencing in two Illumina Hi-Seq lanes. Sequences were de novo assembled using the dDocent and loci sequences were blasted against a Galaxea genome to verify their origin. Clone individuals and loci under selection were removed, and population structure and migration was studied. High levels of gene flow could be confirmed along the Ryukyu archipelago, but small to not existent in East-West direction between Okinawa, Daito and Ogasawara. This was consistent with GPS track data of Microstar bouyes predicted dispersal pathways based on ocean currents. Preliminary results of this project were presented at the Ocean Sciences Meeting in Portland February 2018 as a poster.
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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
Research has progressed as planned.
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| Strategy for Future Research Activity |
RAD sequencing for phylogenetic study over Indo-Pacific (~130 samples) by Illumina HiSeq and MiSeq in collaboration with HIMB in Hawai'i and other international collaborators. The analysis for genetic differentiation between isolated island systems such as the Daito and the Ogasawaran Islands will be finished and compared with ocean current patterns. Demographic models distinguish continuous, ancient migration and secondary contact gene flow scenarios. The phylogeographic project of the genus will be the focus in this year. A nuclear phylogeny and mitochondrial haplotype network will be presented at the international conference APCRS. Two papers are being prepared for publication in international journals: one considering the genetic connectivity between Okinawa, Daito and Ogasawaran islands, and a second considering the phylogeographic evolution of the genus Galaxea.
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