Fig. 2. Trophoblast defects in type I mutants. (A-Q) All conceptuses on the left of each image are either wild type or heterozygous for the Ets2 mutation, and those on the right are either type I or type II homozygous mutant littermates, showing the expression profile (either single- or double-probe in situ hybridization) of the indicated gene transcripts. All are sagittal views and, where applicable, posterior is to the right. The morphologically identifiable embryonic-extraembryonic junction is denoted by arrowheads. (A-E,J,N,P,Q) E6.75 control conceptuses and their type I mutant littermates, with the exception of P, where a type II mutant is also included. For A and J, the image on the right is a magnification of the image to its left. (F,G) E7.75 control conceptuses and their type I mutant littermates. The chorion is marked by an asterisk. (H,I) E6.75 control conceptuses and their type II mutant littermates. (K-M,O) E5.5 control conceptuses and their homozygous Ets2^db1/Ets2^db1 mutant littermates with a reduced trophoblast region (prospective type I mutants). Conceptuses in K are semithin sections. Scale bars: 100 µm. All images without scale bars have the same magnification as A.