Germline cysts: a conserved phase of germ cell development?

Germ cells in many vertebrate ann invertebrate species initiate gametogenes is by forming groups of interconnected cells known as germline cysts. Recen t studies using Xenopus, mouse and Drosophila are beginning to uncover the cellular and molecular mechanisms that control germline cyst formation and, in conjunction with morphological evidence, suggest that the process is hi ghly conserved during evolution. This article discusses these recent findin gs and argues that cysts play nn important and general role in germline dev elopment.