a^x

This allele comprises a deletion of approximately 100 kb, which does not affect agouti coding sequences, but begins 4 kb 3' of the last exon, and thus may affect coat color by removing an agouti 3' enhancer. The Ahcy gene, which codes for the enzyme S-adenosylhomocysteine hydrolase (SAHase), is contained within a 20 kb region within the a(x) deletion. (J:17867)