Mitotic activity of germ cells during normal development of Xenopus laevis tadpoles.

Data on the spatio-temporal pattern of germ cell proliferation in Xenopus laevis tadpoles were obtained, tracing the germ cells from the cloacal position forward. This spatial pattern in germ cell distribution and its change during normal development clearly coincided with histological observations of germ gland development. By application of regression lines to the analysis of this complex pattern, an interesting conclusion about the mitotic activity of germ cells was suggested. While the mitotic activity of germ cells before sexual differentiation shows a regional difference along the germ-cell-containing ridge (GCCR), the doubling time of sexually differentiated gonia seems to show a uniform value over the whole GCCR.