Definition of Primordial Germ Cell

Primordial germ cells are an intermediate in the developmental pathway of germ cells in mammalian embryos. The term "germ cell" is used to refer to a gamete or any cell that has the capability of becoming a gamete (egg or sperm).

Characteristics

• The authors of "Stem Cell Biology" define primordial germ cells as diploid germ cell precursors that exist briefly in the developing embryo before differentiating to become germ cells. This definition indicates that, unlike gametes, primordial germ cells are diploid (they contain two complete sets of chromosomes), they exist briefly, and they retain some stem cell properties.

Origin

• According to Rebecca Burke and Jackie Parente of Brown University, primordial germ cells segregate themselves from other cells in the early embryo before multiplying and moving to the genital ridges. Upon reaching their final destination, the primordial germ cells begin their final differentiation into germ cells.

Significance

• As primordial germ cells retain stem cell characteristics and are present relatively early in development, they have been studied as a possible alternative to using embryonic stem cells, which arise later in development.