泥鳅原始生殖细胞的发生、迁移和性腺分化

通过光学显微镜对泥鳅原始生殖细胞（Ｐｒｉｍｏｒｄｉａｌｇｅｒｍｃｅｌｓ，即ＰＧＣｓ）的发生、迁移和性腺分化进行初步研究，发现泥鳅ＰＧＣｓ最初出现在原肠晚期预定中胚层内，体节中胚层与侧板中胚层分离后而位于侧板中胚层．随着胚胎进一步发育，ＰＧＣｓ沿着脏壁中胚层从消化道腹侧迁移到背面，进入系膜两侧的背壁上皮形成的生殖嵴，与生殖嵴共同组成未分化的生殖腺，此时的原始生殖细胞为性原细胞．ＰＧＣｓ在迁移过程中数量基本不变．另外，未分化生殖腺的不对称分布可能是雌雄分化的最早特征．

STUDIES ON THE ORIGIN AND MIGRATION OF THE PRIMORDIAL GERM CELLS AND GONAD DIFFERENTIATION IN THE LOACH (MISGURNUS ANGUILLICAUDATUS) EMBRYO

The origin and migration of the primordial germ cells (PGCs) and the gonad differentiation of loach were studies by light microscope.The PGCs first appeared in the mesoderm of the late gustrula,After the separation of somites and lateral mesoderm PGCs were found in the lateral mesoderm.Then,PGCs migrate from ventral side to the dorsal side of dipestive tract a long the splanchnic mesoderm and from the germinal ridge with the mesoderm cells which come from somites mesoderm together.The amount of PGCs keep constant during the migration.The study suggested that the unsymmetry of berminal ridge may be the earliest symbol of sex differentiation and sex reversin may take plce during the gonad development of loach.