I-GS segregating in an Australian shepherd dog (AS) pedigree. Squares are males and circles are females, and the arrow indicates the proposita. Open and partially filled symbols indicate dogs that were clinically healthy as determined by physical examination, if genotyped, or by family history, if not. Symbols filled in the upper left quadrant indicate dogs that were genotyped at the KNS2 locus, and symbols filled in the upper right quadrant indicate dogs genotyped for the AMN c.3G>A mutation. Symbols filled in the lower right quadrant indicate dogs determined by genotyping to be heterozygous (G/A) at the mutation site. The 3 clinically affected dogs, indicated by symbols filled in all quadrants, were genotyped at both loci and determined to be homozygous A/A at the mutation site. The 2 symbols filled in the lower right but not the upper right quadrant indicate dogs that were inferred from family data to be heterozygous at the mutation site. The female dog labeled A is an ancestor common to all dogs in the kindred determined to be carriers of the c.3G>A AMN allele.