Genetics W3031 2002
Some Coat Color loci in Felis sylvestris catus
Tabby (T) T--dominant. Mackerel tabby stripes

t--recessive. Classic tabby stripes

Agouti (A) A--dominant. agouti pattern

a--recessive. non-agouti

Black (B) B--dominant. Black

b--recessive. Brown

Piebald spotting (S) S--dominant. White spotting

s--recessive. No white spots

X-linked orange (O) O--Orange color

o--non-orange color

Genotypes for examples in class:

Standard wild-type. A generic housecat 

aka Mackerel tabby

o/o or o/Y ; B_; A_; ss; T_
Classic (blotched) tabby o/o or o/Y ; B_; A_; ss; tt
White spotted classic tabby o/o or o/Y ; B_; A_; Ss; tt
Black and white o/o or o/Y ; B_; aa; Ss; ??
Orange and white classic tabby O/O or O/Y; ??; ??; Ss; tt
Calico (classic stripes) O/o; B_; aa; Ss; tt

Some genetic interactions in these examples:

Orange (O) is epistatic to: B_, bb, T_, tt, aa

Non-agouti (aa) is epistatic to T_, tt, o

S is epistatic to all in cells where S is expressed

S exhibits variable expressivity at the level of the organism and variable penetrance at the level of individual cells.

O/o exhibits mosaic expression. It can also exhibit variable expressivity of O and o.