Pattern formation in amphibian embryos prevented from undergoing the classical "rotation response" to egg activation.

Fertile Xenopus laevis eggs were immobilized so that they were prevented from undergoing the "rotation response" to activation. Many of those unrotated eggs developed through organogenesis, indicating that egg rotation is not a prerequisite for normal early embryogenesis. Various aspects of the regulation of pattern formation were analyzed in unrotated eggs: It was discovered that a substantial rearrangement of yolk platelets occurred without affecting subsequent pattern formation. The germ plasm, however, remained localized in the vegetal hemisphere in inverted eggs. Cleavage furrows and the site of involution were both often observed in novel locations in inverted eggs which were prevented from rotating during activation.