Histological analysis of embryos of wild-type, heterozygous, and homozygous mutants. Wild-type (+/+), GRIM-19+/−, and GRIM-19−/− embryos were dissected at 5 μm at E5.5, E6.5, E7.5, and E8.5 as indicated. The sections were stained with hematoxylin and eosin. The objective magnifications are indicated. Scale bar = 100 μm.