Mosaic patch patterns in chimeric and transgenic mice suggest that directional growth in the adrenal cortex begins in the perinatal period.

Staining for beta-galactosidase (beta-gal) reporter activity in adrenal glands from adult, fetal and neonatal 21-OH/LacZ transgenic mice revealed mosaic patch patterns that were qualitatively similar to those seen in LacZ <--> wild-type mouse chimeras, at similar developmental stages. This suggests that, as in chimeras, the transgenic patch pattern may reflect cell lineage relationships. Consequently, 21-OH/LacZ transgenic mice could be useful as a simpler alternative to chimeras for the analysis of clonal growth and cell mixing during adrenocortical organogenesis.