Page 80 - 《水产学报》2025年第5期

王金霓，等 水产学报, 2025, 49(5): 059607

Sexual difference of embryonic germ cells in Pelodicus sinensis

1,2
3
2
1,2
WANG Jinni , HUANG An , SUN Wei , QIAN Guoying ,
1,2
1,2*
XIAO Ling , GUO Yin , GE Chutian 1,2*
1. Institute of Animal Sex and Development, Zhejiang Wanli University, Ningbo 315100, China;
2. College of Biological and Environmental Sciences, Zhejiang Wanli University, Ningbo 315100, China;
3. College of Fisheries and Life Sciences, Shanghai Ocean University, Shanghai 201306, China
Abstract: The Chinese soft-shelled turtle (Pelodiscus sinensis) is a valuable aquaculture species in China that exhibits typical
sexual dimorphism and is classified as GSD (genetic sex determination) species due to the presence of ZZ/ZW micro-sex chro-
mosomes. However, the development and differentiation of germ cells in the gonads of male and female P. sinensis have been
rarely studied. To characterize the profile of germ cells in both male and female developmental gonads, we utililzed embryos at
developmental stages 14 to 20, which encompassed the sex determination and sex differentiation periods of P. sinensis. Germ
cells from stages 14 to 20 were sampled, and their morphology was examined using tissue sections. Immunohistochemistry was
employed to detect the expression of related proteins, while RNA was extracted from gonads at stages 14 to 20 for RNA-seq
and qPCR analyzes to investigate the differential expression of male and female germ cell-related genes. Germ cell marker
genes included Ddx4 and Dazl, while genes associated with reproductive cell growth and development included Mael,Dnd1,
Stra8 and Dmc1, Rbm38, Hes1, Notch and Bcl2. The tissue sections revealed that germ cells in the embryonic stage were larger
than surrounding somatic cells, with large nuclei and prominent nucleoli in both ZW female and ZZ male gonads. Immuno-
fluorescence staining of DDX4 showed no differences in germ cell distribution between male and female gonads from stages 14
to 17. However, from stage 17 to 20, germ cells in the gonads of ZZ females were concentrated in the cortex, whereas male
germ cells were concentrated in the medulla. RNA-seq analysis indicated that Ddx4, Mael, Dazl, Dnd1, Stra8 and Dmc1 were
highly expressed in female gonads, while Rbm38, Hes1, Notch and Bcl2 were highly expressed in male gonads during stage 17
to 20. Quantitative Real-time PCR analysis confirmed that mRNA expression levels of the germ cell-related genes Ddx4 and
Dazl were significantly higher in ZW female gonads than in ZZ male gonads. Similarly, expression levels of meiosis-related
genes Stra8 and Dmc1 were significantly higher in ZW female gonads. These results elucidate the differences in the develop-
ment of male and female reproductive cells and the timing of differentiation. This study provides an important reference for
research on turtle germ cell development and supports sex control breeding efforts in P. sinensis.
Key words: Pelodiscus sinensis; germ cell; embryo; sex
Corresponding authors: XIAO Ling. E-mail: xiaoling@zwu.edu.cn;
GE Chutian. E-mail: cge@zwu.edu.cn

Funding projects: Natural Science Foundation of Zhejiang Province (LTGN23C190006); the Program of Yongjiang Talent
(2022B-033-G); Zhejiang Provincial Top Discipline of Biological Engineering (Level A), Zhejiang Wanli University
(ZS2022003); Natural Science Foundation of Ningbo City (2022S235, 2022J187)

https://www.china-fishery.cn 中国水产学会主办 sponsored by China Society of Fisheries
12