Fig. 3.

Tracking of β-Gal-positive melanoblasts in embryogenesis. Embryos of the indicated genotypes were harvested at 12.5 days of gestation and processed for β-Gal labeling. Arrows point to individual β-Gal-positive melanoblasts in the dorsolateral migration pathway underneath the surface ectoderm in the trunk area. (A-E) Note similar distribution but slightly reduced numbers and densities of β-Gal-positive melanoblasts in embryos carrying a mutant Mitf allele together with the Kit^tm1Alf allele as opposed to a wild-type Mitf allele along with the Kit^tm1Alf allele, consistent with earlier findings that Mitf gene dosage affects melanoblast numbers early in development (Hornyak et al., 2001). (F) Melanoblasts in embryos double heterozygous for Mitf^mi-bws and Kit^tm1Alf are very sparse and largely restricted to the area over the neural tube.