Tools for the genetic analysis of germ cells.

Germ cells are essential for the propagation of individual species. Studies on germ cell development in mice highlight important biological paradigms. Beginning with their first appearance around embryonic day 7 (E7), germ cells undergo specific cellular changes at different stages of their embryonic and adult development. Germ cells migrate through the hind-regions of the embryo to eventually home into the developing gonads. Further differentiation and development of germ cells differ in males and females. The processes involved in germ cell development and their eventual differentiation into sperm and oocytes have been under extensive investigation in recent years. Studies on germ cells have shed light on the cellular and molecular processes involved in their specification, migration, proliferation, death, and differentiation. These studies have also revealed much about maintenance of stem cell populations and fertility. Here we review the genetic tools that are at present available to study germ cells in the mouse. (c) 2009 Wiley-Liss, Inc.