A COMPARISON OF RIBOSOMAL GENE AMPLIFICATION IN UNI- AND MULTINUCLEOLATE OOCYTES

The amplification of ribosomal RNA cistrons could not be demonstrated in the uni-nucleolate oocyte of the starfish, Asterias forbesii, by methods which demonstrate gene amplification in other forms which contain multinucleolate oocytes. RNA-DNA hybridization and ribosomal DNA satellite density failed to demonstrate the presence of excess DNA in the germinal vesicle as has been found in certain amphibians and insects. Ovarian ribosomal cistron amplification was found in a previously unreported form, the teleost, Roccus saxatilis. The results suggest that multiple nucleoli, or extensive and diffuse RNA granular bodies in oocyte development, are indicative of ribosomal gene amplification. Single, compact nucleoli in oogenesis may indicate the lack of such amplification mechanisms. © 1969.