called
"RED"
The picture was taken 30 minutes after the last pup was whelped.
Notice the only pigment (color) visible are the facial markings and one
pup has a spot on the loin area.
With the exception of any facial markings or body spots, ACD's are born
white (due to the extreme pie bald gene, "s^w"). Body spots are due to
the piebald gene, "s^p". They start to color out at around 3 weeks of
age. Some color out a little sooner, some a little later. This coloring
continues sometimes until the puppy is past 6 months old. Some
owners have said their ACD grew darker or lighter until they were past 6
years of age.
The "red" ACD is genetically a sable ("a^y").
The genes involved in a "red" ACD and ASTCD are (I will talk about what could
be present on another page):
E Locus : E -- extension of eumelanin or phaeomelanin in coat
B Locus : B -- black pigment, acting only on eumelanin (black/brown)
D Locus : D -- full color, not dilute
C Locus : C -- full color, not dilute
A Locus : a^y -- sable
K Locus : k -- non dominant, non-brindle, allows A Locus alleles to be expressed.
T Locus : T -- ticked (pigmented hairs in an otherwise white coat)
S Locus : s^w -- extreme white, dogs that also have body spots are said to also be s^p -- piebald
G Locus : g -- non-graying
M Locus : m -- non-merle (ACD's are not merled)
A typical "red" ACD may have a genotype that looked like this:
E/E B/B D/D C/C a^y/a^y k/k T/T s^w/s^w g/g m/m
OR: if they had body spots -- s^p/s^w, instead of s^w/s^w
When one parent is "ticked-black/tan", the genotype will look like this:
E/E B/B D/D C/C a^y/a^t k/k T/T s^w/s^w g/g m/m
Every gene is the same as with the "ticked-black/tan" ACD, with the exception of the alleles located on the A
Locus. The "red" ACD is a^y, meaning sable. When one parent is "ticked-black/tan" and one is "red", the
offspring receives a copy of the tan point gene from the "ticked-black/tan" parent and a copy of the sable gene
from the "red" parent. The genotype now looks like: a^y/a^t --- sable is incompletely dominant to tan points, so the
puppy will be red, but because of the a^t, the coloration will have a black overlay.
Incompletely dominant means that one allele does not completely dominant another --- both colors can be
expressed.
