Increased blood apoptosis in adult crs heterozygotes. Kidney smears from wild-type (A,C) and heterozygous (B,D) adult crs animals showing hematopoietic progenitors and mature blood cells by Wright-Giemsa staining (A-B) or TUNEL (C-D) with nuclei shown by DAPI (4,6 diamidino-2-phenylindole; blue) and TUNEL (green) labeling dying cells.