Primordial germ cell migration in the Ceratitis capitata embryo.

In this study we followed the behavior of germ cell precursors in the early embryo of the dipteran Ceratitis capitata using conventional fluorescence, laser scanning confocal and transmissiom electron microscopies. During cellularization the pole cells formed a cluster which lodged in a roundish break in the blastoderm at the posterior pole of the embryo. When gastrulation began, the pole cells shifted dorsally and during elongation of the germ band moved into the posterior midgut primordium. Pole cell morphology suggested that these cells were motile until the early stages of development.