The inhibitor gene controls the production of pheomelanian (yellow) pigment. This is a DOMINATE gene! So the Inhibitor gene removes the yellow pigment from the hair shaft. A kitten can receive this inhibitor gene from either parent but only when one or both parents has the inhibitor gene.
The degree of white undercoat is controlled by poly genes. 90% of cats with the Inhibitor gene will show a white base to the hair shafts near the skin.
Remember that cat breeds can have domestic shorthairs, oriental short hairs and other cat breeds in their pedigrees. Some times these are indirect or direct which cause recessive genes to crop up at any time when both parents have said recessive gene.
The inhibitor gene is different than the Color point restriction gene as shown bellow in the diagram. A cat can be affected by both genes at the same time. The inhibitor gene controls the production of pheomelanian (yellow) pigment. The bellow diagram shows what colors will result when a color is affected by Inhibitor Gene.
