The sh339 and qmc554 alleles of gfi1b. (A) Genomic maps of the wt, sh339, and qmc554 alleles of gfi1b, including information about transcripts and splice products. Additional annotations are provided in the inset. (B) Gfi1b protein products encoded by the wt and the 2 mutant gfi1b mutant alleles. (C) PCR amplification of exon 3 sequences and subsequent sequencing are used to identify sh339 carriers. The panels show examples of Sanger DNA sequencing reads. A missing G in a stretch of 5 consecutive Gs on the template strand defines the sh339 allele. As the mutation in sh339 eliminates a BslI restriction site, a restriction digest can also distinguish wt and mutant gfi1b alleles. (D) PCR amplification of exon 4 sequences distinguishes the wt allele and the deletion allele qmc554 of gfi1b. The expected wt and qmc554 PCR fragments are 305 and 109 bp long. Primer sequences are provided in supplemental Table 8. (E-H) Lateral views of embryos stained by WISH. Yellow, green, and red arrows point at gene expression in inner ear hair cells, in the ventral wall of the dorsal aorta, and in prRBCs, respectively. Red arrowheads highlight the lack of gene expression in prRBCs. Genotyping of 3 of the 10 embryos with elevated gfi1aa expression in panels E-F revealed that they were homozygous mutants. Representative examples are shown. All embryos shown in panels G-H display the same gfi1aa expression pattern, irrespective of their gfi1b genotype.