Homozygous viable. Nonsense alleles identified by amplicon sequencing. The gk5239 mutation is A->T, flanking sequences AAATTTTAAAAGACTCGGACAAATGCATCG and CATCGTGTATCTTCGAAGTTAGCCTGAAAA. The gk5240 mutation is G->A, flanking sequences ATGCTGACACCAATCACTGCCCTCTTGGAT and GACCTTCTCCACCAATACTTCTTACTGTTA.