Population genomic analysis reveals a polygenic sex determination system in Apostichopus japonicus
Chunxi Jiang,
Shilin Liu,
Yujia Yang,
Wei Cui,
Shuai Xu,
Irène Rasoamananto,
Thierry Lavitra,
Libin Zhang,
Lina Sun
Affiliations
Chunxi Jiang
CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; Laboratory for Marine Ecology and Environmental Science, Qingdao Marine Science and Technology Center, Qingdao 266237, China; Key Laboratory of Breeding Biotechnology and Sustainable Aquaculture (CAS), Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; University of Chinese Academy of Sciences, Beijing 100049, China
Shilin Liu
CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; Laboratory for Marine Ecology and Environmental Science, Qingdao Marine Science and Technology Center, Qingdao 266237, China; Key Laboratory of Breeding Biotechnology and Sustainable Aquaculture (CAS), Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; University of Chinese Academy of Sciences, Beijing 100049, China
Yujia Yang
The Key Laboratory of Mariculture, Ministry of Education, Ocean University of China, Qingdao, China
Wei Cui
CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; Laboratory for Marine Ecology and Environmental Science, Qingdao Marine Science and Technology Center, Qingdao 266237, China; Key Laboratory of Breeding Biotechnology and Sustainable Aquaculture (CAS), Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; University of Chinese Academy of Sciences, Beijing 100049, China
Shuai Xu
CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; Laboratory for Marine Ecology and Environmental Science, Qingdao Marine Science and Technology Center, Qingdao 266237, China; Key Laboratory of Breeding Biotechnology and Sustainable Aquaculture (CAS), Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; University of Chinese Academy of Sciences, Beijing 100049, China
Irène Rasoamananto
Institut Halieutique et des Sciences Marines (IH.SM), University of Toliara, Toliara, Madagascar
Thierry Lavitra
Institut Halieutique et des Sciences Marines (IH.SM), University of Toliara, Toliara, Madagascar
Libin Zhang
CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; Laboratory for Marine Ecology and Environmental Science, Qingdao Marine Science and Technology Center, Qingdao 266237, China; Key Laboratory of Breeding Biotechnology and Sustainable Aquaculture (CAS), Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; University of Chinese Academy of Sciences, Beijing 100049, China
Lina Sun
CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; Laboratory for Marine Ecology and Environmental Science, Qingdao Marine Science and Technology Center, Qingdao 266237, China; Key Laboratory of Breeding Biotechnology and Sustainable Aquaculture (CAS), Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; University of Chinese Academy of Sciences, Beijing 100049, China; Corresponding author
Summary: The sea cucumber Apostichopus japonicus, a key species in Chinese aquaculture, plays a significant evolutionary role within the Echinodermata phylum. However, the sex determination mechanism in this species remains poorly understood. Here, we conducted extensive sex surveys and sampling of eight wild populations, investigating the sex-related SNPs and insertion or deletions (indels) through bulk segregation analysis (BSA) and genome-wide association study (GWAS) analysis. Our findings suggest that A. japonicus employs a polygenic sex determination (PSD) system, with solute carrier family 8 (SLC8A) being the candidate gene for sex determination, encoding sodium-calcium exchanger (NCX1). The analysis of normalized sequencing depth reveals variations across chromosomes 6, 13, 14, 16, and 18, supporting the PSD system. We also identified 541.656 kb of male-specific sequences and screened five markers (C77185, C98086, C64977, C125, and C876) for molecular sex identification. Overall, this study provides new insights into A. japonicus sex determination, highlighting a complex multi-gene mechanism rather than a simple XX/XY system.
