Homozygous viable. Nonsense and splicing alleles identified by amplicon sequencing. The gk5200 mutation is C->T, flanking sequences GAGAAACAAATATGCATTGAGTCACCGATT and AGAAGCGGCATCCAAGATCTTTTCATGATA. The gk5201 mutation is G->A, flanking sequences TCTTTTTTTCAACTAATCTACATACTTCCA and GGCTCACTGGATTTTTCACTCTTACCATCA.