C In situ hybridisation of ptch2, nkx2.2a and olig2 transcripts in wild type, MZgrk2 and grk2-GFP injected MZgrk2 24hpf embryos. Each panel shows a full view of the embryo on the left and a cross sectional view of a somite on the right. (n=30 for each sample). Scale bars, 200μm (whole mounts), 50μm (sections). 