On the Rna Synthesized During the Lampbrush Phase of Amphibian Oögenesis

Lampbrush chromosomes have been observed in the growing oocytes of animals ranging from mollusks to mammals. They are present throughout the diplotene of the first meiotic division. These elongate, paired structures bear many thousands of loops projecting laterally from the main chromosomal axis, and they are characteristically accompanied in the nuclear sap by several thousand small nucleoli. It was long ago suggested that the organization of the egg and the early processes of embryogenesis were the result of nuclear activity occurring during ovarian oogenesis,(1) and we now know the lampbrush chromosomes of amphibian oocytes are in a state of intense genetic activity.