Phylogeny and genetic diversity of Echinometra sea urchin in Taiwan

ABSTRACT

Four closely related Echinometra species exist in the Indo-Pacific region, but little is known about their population genetics in Taiwan, an area rich in marine biodiversity. Echinometra dominates the Douziping coral reef off Liuqiu Island, where urchin barrens are also present. To understand the relationship between Echinometra species and urchin barrens, we investigated the genetic diversity of Echinometra species in Taiwan by using a nondestructive DNA extraction method on the spines of sea urchins. Mitochondrial DNA results showed that E. sp. C is the dominant species in Taiwan, with relatively high interspecific genetic distance. The E. sp. C is the only species in Douziping, and its population is expanding in accordance with the significantly low R2 value, the significantly negative Fu’s Fs values, and mismatch distribution analysis results. Gene flow estimates between the urchin populations in Taiwan and those in the neighbouring waters of Okinawa suggested that the Kuroshio Current could play an important role in Echinometra dispersal. This implies strongly connectivity between these populations. This study reports the first case of E. sp. C-associated urchin barrens in the tropics.

KEYWORDS:

• Echinometra
• mitochondrial DNA
• population expansion
• urchin barrens
• Kuroshio Current

Acknowledgements

We thank Prof. Sung-Yin Yang (National Chiayi University), Dr Shyh-Min Chao, Mr Kwen-Shen Lee (National Museum of Natural Science), Kenting National Park, Penghu County Government, and Pingtung County Government for their assistance with sample collection and sampling logistics. We gratefully acknowledge the assistance from the members of the Marine Genomics and Evolution Laboratory at the College of Marine Sciences, National Sun Yat-sen University. We thank the reviewers for their constructive comments. All authors contributed to the study’s conception and design. Material preparation, data collection and analysis were performed by Mei-Fang Lin, Yi-Yuan Lin, Ming-Che Yang and Sheng-Chi Chung. The first draft of the manuscript was written by Mei-Fang Lin and all authors commented on previous versions of the manuscript. All authors read and approved the final manuscript.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the National Science and Technology Council [grant number MOST 111-2611-M-110-005]. Mei-Fang Lin has received research support from the National Science and Technology Council and National Sun Yat-sen University (NSYSU) within the framework of the Higher Education Sprout Project by the Ministry of Education in Taiwan.