Proceedings of CWMD International Conference 2019
September 19-21, 2019, Kumamoto University, Japan

Comparison of genetic structure of commercially important precious corals
Carallium japanicum and Pleurocorallium konojoi using genome wide SNPs
Kenji Takata1, Hiroki Taninaka2, Masanori Nonaka3, Fumihito Iwase4, Taisei Kikuchi5,Yoshihisa Suyama6, Satoshi Nagai7, Nina Yasuda1
1Graduate School of Agriculture, Faculty of Agriculture, University of Miyazaki 2Interdisciplinary
Graduate School of Agriculture and Engineering, University of Miyazaki 3Okinawa Churashima
Foundation Reseach Center 4Shikoku Marine Life Laboratory 5Parasitology, Faculty of Medicine,
University of Miyazaki 6Field Science Center, Graduate School of Agricultural Science, Tohoku
University 7Japan Fisheries Research and Education Agency, National Research Institute of Fisheries
Science, Research Centre for Bioinformatics and Biosciences Environmental genomics group
E-mail: nina27@cc.miyazaki-u.ac.jp
Keywords: precious coral, deep sea, MIG-seq, genetic diversity, gene flow
Abstract
Deep sea corals used for jewelry are often refer to as “precious coral” and are often harvested inMediterranean Sea, Japan, Taiwan, Midway, and Hawaii. They are normally found at a depth of 100 mor deeper with low density except for Mediterranean Sea where the species can be found much shallower
depth (e.g. 40 m). Precious corals are not only commercially important but also essential as a foundation
species in the deep sea environment. Currently precious coral species populations are highly threatenedby overfishing and illegal fishing. Although sessile and the larval duration of precious coral are unknown,
they appeared to have larval dispersal period before settlement. Thus, to conserve precious corals, it isimportant to know how their populations are genetically connected via larval dispersal in each species.
In this study, we examined population genetic structure and genetic diversity of two precious coralspecies in Japan (Corallium japanicum and Pleurocorallium konojoi). We collected in total 118 colonies
from two populations separated by 40 km for the two species around south western Shikoku. Nuclear
genome-wide SNPs were obtained and analyzed using Multiplexed ISSR genotyping by sequencing(MIG-seq). Based on 478 SNPs that are obtained from C. japanicum and P. konojoi in common, thegenetic differentiation coefficients, global FST indicated significant genetic structure in C. japanicum(FST =0.097, P=0.002), while no significant genetic structure in P. konojoi (FST =-0.016, P=0.943). Thesedata suggest higher level of larval dispersal in P. konojoi than that in C. japanicum. This data suggests
recovery of damaged C. japanicum population via larval dispersal from other population would be more
limited and more difficult than P. konojoi population. The data highlighted the importance to avoid local
extinction of C. japanicum populations by decreasing fishing pressure, given that C. japanicum is themost expensive and the most intensively fished precious coral in Japan. On the other hand, genetic
diversities (expected heterozygosity He) of C. japanicum (0.087-0.104) were higher than that of P.
konojoi (0.026-0.032). Because genetic diversity is an indicator of population persistence throughenvironmental changes, P. konojoi would be more vulnerable to environmental changes including
anthropogenic environmental stress and climate change than C. japanicum.