Primordial germ cells (PGCs) constitute an embryonic cell type that migrate to gonadal precursors and form the gametes. In many animals, PGCs are set apart from somatic cells early during embryogenesis. These cells migrate to gonadal precursors and then constitute gonads so they are useful models for cell motility studies. They have a highlighted importance for development and reproduction studies. Primordial germ cells have morphological differences from the somatic cells. Structure of these cells can be detected with light and electron microscopy in early development stages. This review describes the morphological, histological, molecular and ultrastructural features of primordial germ cells in different animals and gives an overview for simplified identification.
Primordial germ cells; ultrastructure; histology; morphology
