Single-cell migration in development - Lessons from germ cells.

Primordial germ cells (PGCs) migrate to associate with somatic cells to form the gonad, generate gametes and thereby ensure fertility. This chapter presents the mechanisms underlying single-cell migration performed by PGCs in various organisms, such as zebrafish, Drosophila, and the mouse models. This review introduces the principles of cell motility, factors controlling directed migration, and the effects of interactions between migrating cells and their environment. Specifically, it discusses passive and active migration mechanisms, the roles of guidance cues, and of interactions with different tissues that influence PGC migration. Comparative analysis of the process in different organisms reveals conserved and distinct strategies for motility and directed migration. The presented mechanisms contribute to broader understanding of cell migration, highlighting PGCs as a useful in vivo model for studying the principles governing the movement of cells within tissues.