Study On The Expression Of Gene Vasa During Gonadal Natural Sex Reversal Of Ricefield Eel (Monopterus Albus)

Using in situ hybridization with DIG antisense RNA probe, we detected the expression of gene vasa during the gonad development of Monopterus albus. The results are as follows: During oogenesis, the expression of vasa mRNA can be detected in the cytoplasm of â… , â…¡ ,â…¢ stage oocytes. It is not very obviously that the vasa mRNA concentrate at cortical region of stage â…£,â…¤ oocytes. The signals of vasa mRNA can also be observed in the degenerated oocytes. We detect some vasa mRNA positive cells in the membrane of â…¢, â…£ stage ovary, and these may be the primordial germ cells (PGCs)which migrate to the membrane of ovary and will differentiate to spermatogenia. These PGCs will migrate to the seminiferous tubule and develop into spermatids during the sexual reversal. The expression of vasa mRNA in mature testis is restricted to the spermatogonia and spermatocytes. We examined the Monopterus albus ovary and testis by alkaline phosphatase staining and found that there are alkaline phosphatase positive cells in the membrane of ovary; in mature testis, the male germ cells in the gonadal sac are alkaline phosphatase positive while no alkaline phosphatase positive cells were found in the membrane of testis. The results suggest: The male germ cells of Monopterus albus may derive from the PGCs in the membrane of ovary.