Abstract
Studies examining the messenger RNA population present in Xenopus laevis oocytes and early embryos are discussed. There may be two classes of mRNA present in the oocyte, one which is used by the developing germ cell and the other which is synthesized during early oogenesis and stored for translation after fertilization. During oocyte maturation the mRNA population undergoes a dramatic qualitative change in which the length of the pA tail is altered. The behavior of individual sequences, including actin and ribosomal proteins, is described during maturation and early embryogenesis.