Single-cell RNA sequencing reveals the gonadal dynamic changes of sex differentiation in hermaphroditic protogynous orange-spotted grouper, Epinephelus coioides

In teleosts, the molecular mechanisms of sex differentiation are diverse and unclear, especially in hermaphrodite fish. In the present study, 15 cell types, including germ cells, follicle cells, and theca cells, and so on, were identified using single-cell RNA sequencing (scRNA-seq) in the gonads during sex differentiation in a hermaphrodite fish, orange-spotted grouper (Epinephelus coioides).

Two pre-follicle cell types were defined, and the differentiating trajectories of the follicle cells were outlined. Notably, both pre-follicle and follicle cells highly expressed male-related genes synchronously, such as amh, sox9, and dmrt3 in pre-follicle cells, as well as dmrt1 in follicle cells. Oocyte possessed two distinct states, with high expression of oocyte development related genes in one state and spermatogenesis related genes in the other state, respectively.