COLOURS IN THE BORDER COLLIE
This page is a very basic guide about how the different colour's are produced. Firstly, please let me say that health temperament and soundness should always be given priority over colour when choosing breeding stock. Having interesting colours is just the icing on the cake.
First things first. I need to say that I am NOT a geneticist. I have had a lifelong interest in how different colours are produced in animals, and have spent a great deal of time studying books such as, The inheritance of coat colour in dogs, by Clarence C Little, and Genetics for dog breeders by Roy Robinson. Both very informative books, but even they cannot agree completely on just how some colours are created.
I have been breeding coloured border collies now for over 40 years,
and before that worked for a well respected
poodle breeder, over the years I have managed to produce most of the
colours seen in border collies, with the exception of brindle, which I
still hope to get one day, so my knowledge is based largely on
experience, and study. In recent years I have also seen a number of
'new' colour variations, some attractive and some just plain odd.
Ranging from pups that have the colours reversed (dark where you would
expect light and light where you would expect dark) and a mixture of
colours you would not expect to find on one dog. Which just goes to
prove that nothing in colour breeding is ever 'black or white' and as
the breed evolves we can expect to see more mutations, and variation,
and possibly a whole rainbow of new colours popping up in the breed.
I am sure if you already have a good understanding of genetics, you will already understand the basic principles of colour inheritance, but for those of you who find all the technical jargon a bit mind blowing, I will try to explain it simply, in layman's terms, just to give you some idea. If you want to get a deeper understanding there are plenty of sites around that can explain it all in a bit more depth. There are new colour combinations popping up all the time, some of which are not even written about in detail in the genetic sites and books, but I will try to explain a little about the ones that are most often seen
Every feature of your dog, from the length and colour of its hair, to the size of its ears, and the length of its tail is dependent on its genes. Genes always exist in pairs, and at the time of conception, the pup inherits one of each gene pair from each of its parents. (Otherwise, the total number would keep doubling up,) Each colour, or coat pattern has its own gene pair, that is responsible for its colour, and it is possible for a dog to have the genes for a whole variety of colours, though you may not be able to see some of the colours, they can still be carried, and pop up in future generations.
Which
of the gene pair it inherits from each parent in each case is random,
which is why parents can produce pups of different colours in the same
litter. Genes
can be dominant or recessive. A recessive gene is a mutation of a
dominant gene. The colour you see will depend on whether the pup has
inherited the dominant or the recessive gene from each parent. Dominant
genes are normally shown as capital letters, ( BB = black) while
recessive genes are shown in small letters. (bb = brown) It is possible
for parents that are both a dominant colour to produce pups of a
recessive colour, but it is not possible for two recessive coloured
parents to produce a dominant colour pup.
Coats can come in a whole range of colours, some are more common than others, and they can also come in a variety of different shades, depending on the modifying genes that can also be present. These modifying genes can be responsible for the size and density of the pigment granules in the hair, which is why you can get a range of, for example, brown coloured dogs, that can range from a very dark liver colour to a foxy red, they all have the same brown gene, but the density of colour is controlled by a modifying gene that gives the coat a different appearance, by altering the amount and size of the pigment granules present in each hair ( think of it as watering down the colour).
BLACK Black is a
dominant colour, it is normally shown as BB. (There are 'different
forms' of black, but we do not
need to get into those here) Black can come in a variety of shades
(remember the modifying genes?) some can be jet black, others can
almost seem to have a brown tinge to the coat. A dog that is BB will
not carry or produce any other colour, as it does not have the necessary
recessive colour gene's required.
BROWN Sometimes
called LIVER, or RED. This is a recessive colour. It is a recessive
mutation of black, and is normally shown as bb. (Different shades are
produced by the action of the modifying genes) Both parents have to
carry the brown gene in order to produce a brown pup. A black dog that
has one copy of the brown gene (that it can pass on) would be Bb (Black
carrying brown) A brown dog, has two copies of the recessive brown
gene, so it can only pass on a brown gene, and would be bb. Brown dogs
have inherited a copy of the recessive b gene from each parent, giving
them two copies bb. In order to produce brown, both parents have to
have at least one copy of the b (brown) gene, and pass that copy on to
the pup. Each parent has to be either Bb – black carrying brown – or bb
brown, it is not possible for two brown dogs to produce black pups,
as brown is recessive to black.
BLUE Sometimes
called slate, is produced by the effect of a dilution gene that dilutes
the base colour. If the base colour is black, the result of this gene is
to produce a blue (dark grey) colour, if the base colour is brown; the
result is a diluted brown – milky tea- colour, sometimes called LILAC.
It is normally shown as dd for dilute. A dog that does not carry the
gene for dilute would be shown as DD (non dilute) It is possible for any
colour to be affected by the dilute gene. As with the brown gene, both
parents have to carry the dilute gene, and pass it on to the puppy, in
order to produce a dilute colour. If only one parent carries the colour
and the other does not, you will not be able to produce a diluted colour,
but a proportion of the pups will carry the dilution gene and be able to
pass it on to future generations. It is not possible to produce a non
dilute (black for example) from two dilute (blue) parents. It is
possible to produce a dilute (blue) from two black parents who both
carry the dilute gene, or from one black and one blue so long as the
black parent has one copy of the dilute gene, but if one parent does not
carry the dilute gene, you will not produce dilute pups
SABLE Sable is a
little different, it is shown as ay, and in its pure form it has the
affect of producing a yellow
coat,
this is sometimes called - clear sable -. You are more likely to be
familiar with shaded sable- this is a yellow coat, where the tips of the
hairs are black. There is often a dorsal stripe of more darkly shaded
hair and a mask of darker shading though this can vary in individuals
considerably. Some sables can be so
heavily shaded that they can almost appear to be tri, and saddle pattern
sables where the head and legs are yellow but with a distinct black
saddle, it is possible to get brown sables, where the tips of the hair
and nose lip and eye pigment are brown and a dilute sable or blue sable
where the hair tips and nose lip and eye pigment are blue/grey. You can
also get sable merles, but because of the paleness of the coat these can
be hard to detect from normal sables once they get their adult coat. (
see Rio, he is sable merle) They are quite
easy to distinguish as pups. Sable is recessive to most other colours
with the exception of tri, it is dominant to tri. So in order to produce
sable, both parents have to either be carrying sable, and/or tri. Any
colour can produce sable, if both parents carry the sable gene, or if
one parent carries, or is, sable and the other parent carries, or is
tri. It is not possible to produce sable pups from two tri parents
ee RED sometimes called red – yellow – gold. This is the same gene that is found in yellow Labradors and golden retrievers, along with a number of other breeds. It looks the same as a clear sable, and can vary from Gold to pale cream, there should be no other coloured hairs in the coat. This gene has the effect of stripping the colour pigment out of the coat, a bit like if you washed your hair with peroxide most of the colour would be stripped out. It is a recessive gene and needs to be passed on from both parents in order to show itself in the pup, if the original base colour is black the dog should have black nose/eye/lip pigment, and if the base colour is brown the nose/eye/lip pigment will be brown. I would imagine if the base colour is a dilute then the body colour would be very pale with pigment to match.
People often ask if it is 'safe' to mate two coloured dogs together. There is no hard evidence to suspect that such a mating is going to produce any more problems than mating two black and whites together. Look at other breeds, rough collies, shelties, corgi's, GSD's regularly breed sable to sable. Retrievers and Labradors breed ee dogs together, Weimaraner are all dilutes and Sussex spaniels are all brown, to name just a few, there is no reason to suggest that the repeated mating of coloured dogs together is likely to produce problems or weaken the colour. The only exception to this rule, is with the merle gene, see below.
COAT PATTERNS Coat patterns can be seen in any colour.
MERLE Merle
is a coat pattern, not a colour, the gene that produces the merle
pattern, reduces the pigment in random areas of the coat. So a 'blue
merle’ is really a black and white dog that has had the pigment reduced
in parts of its coat giving it the appearance of a blue/grey dog with
black patches. If these random patches happen to be over the eye area
you get blue or marbled eyes, or if on the nose, lips or eye rim, you
get pink skin. As merle is a pattern, not a colour, it is possible to
produce it in any colour. You do however need to have one merle and one
non-merle parent to produce the merle pattern. It is not possible to
produce merle pups from two non merle parents. As the pigment
reduction is random, and it can also have a tremendous amount of
variation in the amount of pigment reduction you see. It is possible to
sometimes get, phantom merles. These are genetically merle dogs, that
have just a tiny patch of merle hair, maybe only a few hairs, often in a
place where it hardly notices. But as these individuals are genetically
merle, they can still produce merle pups, with normal distribution of
the merle pattern, giving rise to the belief that merles have been
produced from two non merle parents. Mating a merle to an ee red/yellow
is not a good idea, as due to the ee red gene removing all of the black
pigment in the coat, it can be virtually impossible to detect which pups
in the litter are actually genetically merle, and this could result in
accidental merle to merle mating's in the future.
One important thing to remember with the merle gene is that it should NEVER be doubled up on. The merle gene is semi lethal. If you mate merle to merle, the gene can also affect the development of eyes, causing very small or nonexistent eye balls, and predominantly white pups, that can be deaf and sterile. A merle should ALWAYS be mated to a solid colour, it does not matter what colour you mate it to, so long as it is not another merle, also it does not matter if the solid parent has merle dogs in its pedigree, the problems will not be carried down so long as you only have one merle parent.
TRI The
typical Tri markings are also a coat pattern, and as with merle, it can
be produced in any colour. In order for the tri pattern to show itself,
it has to have
two copies of the tri gene, and to have received a copy of the tri gene
from each of its parents. In the case of tri, the gene responsible is
a recessive gene; this simply means that If the pup receives two copies
of the tri gene, one from each parent, you have a tri pup, If it
receives one copy of the tri gene, and one copy of the non tri gene, you
get a non tri pup that carries a single copy of the tri gene, and can
pass the tri gene on to future generations. If it receives two copies
of the non tri gene then you have a non tri pup that does not carry tri
and therefore cannot pass it on to future generations.
I hope this gives you a little insight into how the different colours are produced, and if you find the subject as interesting as I do I hope it will encourage you to delve deeper into the more extensive articles that can be found on colour genetics to obtain an even better understanding of the subject. Please click HERE for a more extensive explanation of the genes responsible for colour.
