|Tan Points and Coat
Located on the "A" Locus ~~ "a^t" or 'tan points' is a common coloration of the
Working Kelpie. This is primarily a solid colored dog with tan (phaeomelanin)
"points" above the eyes, muzzle, chest, stomach and lower legs. The hue can
range from a pale biscuit to a rich ginger to a golden copper in color. Commonly
seen in many breeds like hounds, Dobermans, Rottweilers, Border Collies,
Australian Coolies, Australian Shepherds and Kelpies. In breeds that have the Irish
spotting, along with tan points, this is known as "tri" colored (Australian Shepherds,
Coolies and Border Collies). There are many breeds of dogs with this coloration,
other than the ones listed here.
In order to express the tan point pattern, the dog must have inherited a copy of the
gene from both the sire and dam.
A normal tan point colored dog will also be "k/k" at the "K" locus. When "K" is in the
homozygous recessive form "k/k", this allows the expression of the alleles located
on the "A" locus. In other words, if a dog is "k/k" and "a^t/a^t", then the tan points
will be expressed. If the dog is "K/K" or "K/k" and "a^t/a^t", then the tan point will not
be expressed. The expression of the "A" locus alleles is governed by the alleles on
the "K" locus.
If both parents are tan pointed ("a^t/a^t"), then they are also 'normal' black ("k"),
then all puppies in that litter will be tan pointed, because they inherited a copy of
the tan point gene ("a^t") and normal black ("k") from the dam and from the sire.
Thus, making them "a^t/a^t k/k" -- tan point.
If you see a solid colored pup in a litter, where both parents are tan pointed -- the
sire is not who they think it is or who they say it is. The exception to this are the
non-extension (e/e) red/yellow (cream) colored and dogs that are carrying the
recessive agouti black ("a") on the A Locus.
If one parent is a tan point ("a^t/a^t k/k") and the other is a non-tan point or solid
color (and is homozygous for dominant black - "a^t/a^t K/K"), then all pups in the
litter will be solid -- or non-tan point. However, they will be carriers for the tan point
gene (the gene is hidden). Hidden genes are recessive and therefore; not
expressed. If the tan point is a hidden gene, it is still in the dogs genetic make-up,
just not seen. These hidden genes can be inherited by the offspring. They also
can be carried for many generations and when mated with a dog with the same
recessive gene, the gene will then be expressed (or seen).
If one parent is a tan point ("a^t/a^t k/k") and the other is a non-tan point, but is a
carrier ("K/k a^t/a^t"), then some pups will be tan pointed and some will not be (will
be solid color). It should be more of a 3:1 ratio or 75% with tan points and 25%
without. Ratio's and percentages depend greatly on the litter size.
If both parents are solid colored and both carry the tan point gene ("K/k a^t/a^t"),
then some pups will be tan point, some will not. It should be a 50% with tan points
and 50% without.
Smooth/short coat -- L/L
Medium coat -- L/l [there are different theories to this; some say it's either smooth
coat (L/L or L/l) or rough coat (l/l); some say the mating of the
two causes a medium coat (L/l)]
Rough coat -- l/l
The gene responsible for hair length is Fibroblast Growth Factor 5 (FGF5). The
study by Donna Housley and Patrick Venta was with the Cardigan Welsh Corgi, in
which the long haired variety is called "fluffy".
Many or most Kelpies have a smooth (short) coat, because smooth coats are
dominant to rough/long coats. Having said that, most Kelpies are homozygous
dominant for the smooth coat (meaning both alleles are the same and will always
code for a smooth coat). However, there are some that are heterozygous for rough
coats. Meaning, the alleles are different. There are two alleles, the first is
dominant for smooth (therefore short coat is expressed) and the second one is
recessive (hidden and is carried) and would code for the rough coat.
Sometimes, a Kelpie will be whelped that has a long (rough) coat. This doesn't
necessarily mean there was a hole in the fence during the breeding. Could have
been .... or it could simply mean that both the sire and dam were heterozygous for
coat length. During the early development of the Kelpie breed, a long coated dog
(or dogs) was used; thus the gene for long coat was inherited, passed along and
/or carried for many generations. Or could be that somewhere in the lineage a
rough coated dog (probably a Border Collie) was mated with a Kelpie -- the
resulting offspring were smooth coated (if the Kelpie was homozygous dominant for
smooth) and carriers for the rough coat. If any of these offspring were mated with a
dog that was also a carrier --- their results would be some of the pups would be
smooth coats and some would be rough. If instead, one of the offspring was mated
with a dominant smooth coat, all the pups would be smooth coats and carriers.
This hidden gene (or carried gene) could be passed down for many, many
generations until one day the carrier is mated to another carrier ---- the resulting
litter would have smooth, as well as, rough coats. And the owner would be
scratching his head asking "what in the world happened!!?".
A DNA parentage test will answer many questions, as will researching the pedigree.