Habitat preference and Sea-level change as drivers of genetic diversity and evolution in reef crabs

2022 Fiscal Year Annual Research Report

• Project/Area Number: 22F22078
• Allocation Type: Single-year Grants
• Research Institution: University of the Ryukyus
• Host Researcher: 成瀬 貫 琉球大学, 熱帯生物圏研究センター, 准教授 (30398309)
• Foreign Research Fellow: EVANS NATHANIEL 琉球大学, 熱帯生物圏研究センター, 外国人特別研究員
• Project Period (FY): 2022-07-27 – 2025-03-31
• Keywords: Population Genomics / Ecological Speciation / Habitat preference / Coral Reefs / Crustaceans

Outline of Annual Research Achievements

In FY 2022 we began collecting specimens and genetic data (completed in fiscal year 2023). Fieldwork included a trip to Iriomote Jima, and funded the participation of two Japanese graduate students to help. This work resulted in the collection of many important specimens used for genetic work. We also discovered two new species of crab belonging to the genus Thalamita. A manuscript describing these species in in preparation now, and will be coauthored by a Japanese PhD graduate student from Ryudai.

Current Status of Research Progress

3: Progress in research has been slightly delayed.

Reason

In FY 2022 we successfully began our fieldwork and refined the scope of our study, focusing exclusively on the crab genus Thalamita (~80 species). This approach will enable us to account for evolutionary history when testing for correlations between habitat preference and genetic diversity among closely species. For our population genomic work, we chose to shift to GRAS-Di sequencing; a more advanced techniques developed in Japan by Toyota. GRAS-Di sequencing will enable us to generate greater, higher quality, population genetic data that is more suitable for cross species comparisons of genetic diversity. Originally, we proposed to begin collecting our genetic data in FY 2022, but much of this work could not begin until FY 2023. Nevertheless, we made good progress on our study in FY 2022.

Strategy for Future Research Activity

In FY 2023 we will: (1) finish generating CO1 DNA barcode data for hundreds of specimens (originally proposed to begin in FY 2022); (2) secure genetic tissue samples and unpublished CO1 sequences from American collaborators for 30 target species sampled from across the Indo-Pacific; (3) use GRAS-Di sequencing to generate millions of base pairs of sequence data for up to 196 specimens from 11 species (for population genomics) and 66 species (for phylogenomic comparative analyses). We will present preliminary findings at the Annual Meeting of the Carcinological Society of Japan in Tokyo (October, 2023). Last, we will begin our analyses and preparing manuscripts for publication. Progress made during FY 2022 will make this possible.