Abstract

The developing vertebrate oocyte autonomously makes most of the components of the machinery for DNA and protein synthesis, as well as ‘maternal’ mRNAs, needed immediately after fertilization. However, specialized egg constituents such as yolk proteins, egg white, cholesterol, lipoproteins and egg coat substances, are formed in the liver, oviduct and perhaps in follicle cells. The assembly of the developing egg is therefore a fascinating example of division of labor among oocytes and extra‐oocyte tissues, the coordination of activities of the latter being achieved by hormones.