A series: Agouti (see Copper Inheritance)

B series: Brown (see Red Versus Black)

C series: Chinchilla

Allele	Phenotype
C	full color
cch	chinchilla
ce	extreme dilution
ca	albinism

Complete lack of pigmentation is very rare. Chinchilla has no effect on black and only a slight affect on brown coat color, although in tan colors breed the yellow pigment is reduced to cream with similar changes in brindled or red animals.

D series: Dilution

Allele	Phenotype
D	intense
d	dilute

d results in the blue we see in blue merles, and the yellowish in red merles is a result of the d affecting the dark red. Its affect on yellow is similar to chinchilla.

E series: Extention

Allele	Phenotype
E	normal extention of dark pigment
m	Black mask
e	yellow (restriction of black)

Locus E exemplifies epistasis when paired with the Locus B. E and B working together determine the color of the nose on labradors as well as the yellow color. It used to be believed the brindle occured in this locus. Not so. It may be in the same locus with dominant black. Brindle exists in Australian Shepherds very rarely.

S series: Spotting (See White Inheritance)

M series: Merle (See Merle versus Solid)

Merle affects absence of hair pigmentation, dilution, and eye pigmentiation. It also affects auditory, ocular, and reproductive systems.

Int series: affects yellow dilution in agoutis. Does not exist in Aussies.

G series: Greying

Allele	Phenotype
G	retains birth color
g	turns grey

This is present in Aussies and explains why some Aussies may change blue merle color as they grow.

R series: Roan

verdict still out on what it does. Bear with me

T series: Ticking

Homozygous T genes produce animals born white and producing spots as they grow (Dalmation). Perhaps heterozygous T's are responsible for the ticking or freckling of the Aussie?

For more, please check out this article on Multiple Alleles in Aussies