College of Cat Genetics: Student Seminar 3
by Patricia Turner
I have described the colour effect produced by the action of brown AND dilution on agouti but, so far, have neglected to describe the differences produced by the addition of dilution alone. If dilution is added to the normal black/yellow agouti hair, it converts the black areas into blue but hardly changes the yellow areas at all. Thus the Blue agouti is, in reality, a blue and beige cat.
A recent writer in Cat World described two types of blue dilution, one of them being the blue I describe and the other being the blue of the Siamese. This is a common mistake but nevertheless one that should be corrected. Although there is only one gene for blue, it can look different in different combinations. With Siamese it remains fairly similar, if a little paler, than the colour seen in the solid blue cat; with agouti it becomes blue and beige; with inhibitor it becomes more silvery; with brown it becomes lilac; with sexlinked orange (red) it becomes cream, and so on. Yet it is the same gene. It is the combination possibilities that produce the differences.