Morphology and Regional Distribution of the Primordial Germ Cells in the Giant Freshwater Prawn, Macrobrachium rosenbergii

Abstract

Primordial germ cells (PGCs) of early developing embryos of Macrobrachium rosenbergii were detected at 1.5-2.5 days of development. They were large round cells containing a large nucleus with prominent nucleoli and granulated cytoplasm. They were not reactive to periodic acid-Schiff reaction and showed negative alkaline phosphatase activity. In 6.5-day-old embryo, a cluster of PGCs occupied the dorso-medial region behind the yolky portion. In 14.5-day-old embryo, they were observed at the posterior of the heart. The PGCs were not observed either in the testis or ovary. Only type I spermatogonia showed certain resemblance to the embryo PGCs.