SYNCHRONOUS OOGENESIS IN ENGYSTOMOPS-PUSTULOSUS, A NEOTROPIC ANURAN SUITABLE FOR LABORATORY STUDIES . LOCALIZATION IN EMBRYO OF RNA SYNTHESIZED AT LAMPBRUSH STAGE

An investigation of several tropical frogs was undertaken in order to find species in which synchronous oogenesis takes place, so that the RNA synthesized at the lampbrush stage could be labelled and followed through early development. The reproductive cycle of Engystomops pustulosus was found to include both synchronous and asynchronous phases. Laboratory maintenance and induction of synchronous oogenesis in this organism are described. By using toads carrying out synchronous oogenesis, RNA synthesized during the lampbrush stage was shown to be retained through gastrulation. The pattern of new RNA synthesis in the embryo resembles that in other anurans. Radioautographs suggest that the distribution in the embryo of maternal RNA synthesized at the lampbrush stage is distinct from that of RNA newly synthesized by the embryo; the possible implications of these observations are discussed. Copyright © 1969 Wiley‐Liss, Inc., A Wiley Company