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Coatcolours in Tibetan
Spaniels
By Ragnhild Primdal
(primdal@kennel-sommerlyst.dkl
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Even though colour genetics is well documented,
it is nevertheless a
mouthful to comprehend correctly,
which I hasten to add I do not either! |
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That apart, I have regardless embarked on the subject of
the many colour variations in Tibetan Spaniels, begging forgiveness for
any misunderstandings along the way. In addition I am certain I have not
been able to accumulate every snippet of information available, thus the
text must not in any way be regarded as “the complete works” on the
subject of colour genes in our dogs, but if it can stimulate anyone to dig
deeper and/or to satisfy curiosity, my objectives are secured. |
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The colours of our dogs are controlled by genes located on
its
chromosomes. A canine has 78 chromosomes of which 76 is of the homozygous
(biology – hybrid, carrying genes from similar pairs), whilst the two
remaining are gender chromosomes, which can be heterozygote (biology –
hybrid, carrying genes from different pairs). Most genes are coupled
genes, meaning that they are inherited combined. But, the colour of fur,
its intensity and location on the individual dog, is located on different
chromosomes and is therefore independently inherited.
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Alternatives are
those that can “reserve space” on the same locus (meaning place,
location, as the genes are also
called). These are named Allelés (from the Greek αλληλος allelos, meaning
each other), and it may never be more than one allele on any one locus on
each of the chromosomes in a pair. |
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Often both a dogs phenotype and genotype is discussed. Phenotype is the
visible colour and its variations that we see, and genotype is the
individuals genetic traits, not necessarily visible and that also carries
recessive genes which is controlled by various locuss that makes pale,
intensifies, locates, hinders or hide each other.
. |
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There is, according to C. C. Little, at least 10 different pairs of
chromosomes in a dog, but how many of these are present in a Tibetan
Spaniel is not known, at leat not to me. According to Catherine Marley can
8 be found in Lhasa Apsos and it is reasonable to assume the same number
is present in our dogs, especially as those two breeds has a common background
somewhere in the rather dim past. The sum of the locuses are responsible
for the rich variations in colour and patterns we can see in our dogs.
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Further on in this article, you will find a table listing all of the
alleles assumed to be present in our dogs, hopefully contributing to
understanding.
Every single individual “Tibbie” has two alleles from each of the assumed
eight series og genes. One allele from each series from its mother and one
from its father. The basic, genetic types of colours present can be
defines as follows.
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(click for larger image) |
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1) Sable (golden, red, creme or grey):
It is within this group we will find the greatest number of Tibbies. The
colours are a combination of light or dark hairs in various amounts. Light
ones varies from deep red to light crème or white. Darker ones are
normally black but may also appear liver-coloured or gray, depending on
how many plus or minus factors that enters the equation. Some sable dogs
loose black or dark strands of hair as they grow older but must not be
confused with “clean” colours, that does not have any form of dark
markings at birth.
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ble
Sable |
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2) Pure tan (red, golden, creme or white):
These dogs do NOT have a dark pigment in their coats colour (nor black nor
livercoloured), not even at birth.
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Creme |
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3) Black:
A completely black Tibbie will never have red, golden or crème coloured
strands of hair anywhere, if so it will not be classified as black but as
black & tan, permitted exceptions are white, preferably on its paws or its
chest.
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BBlackBlack |
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4) Black/tan:
It can be difficult to distinguish if a newborn Tibbie is black & tan or
just black, as they both may have white socks and other white markings
hiding the tan. The best place to determine this is under its tail, white
markings are rear in that location, but black & tans normally always shows
tan there, if present. |
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Black/tan |
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The reason for the various markings and colours is, as mentioned earlier,
the individuals various alleles.
The dark portion of the pigment can be reduced ( modified – a minus-factor
), by a large number of other genes. |
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Parti |
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a) Particolor-gene (P) is able to change any one of the four basic
colours, evident by white markings on the body.
b) Gray factor (G), changes dark hair to grey in all basic nuances,
as the dog grows older. Only its snout (the forward facing portion of its
nose), is independt from this allele.
c) Blue gene (d) causes dark or black hair to turn grey, usually
visible at a young age. The snout area on a blue puppy is normally grey
and the eyes either grey or brown like a nut.
d) Liver colour (b) may change black elements in all the basic
colours including in the snout area which normally turns into liver or
brown or, on rarer occasions, yellow.
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nLigth brown
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The lighter pigment in the basic colours can be modified or reduced by
another gene; the so called red/golden dilutive factor designated (C),
that controls de ”depth” of the colour which opens up for it turning into
any hue from deep red to a light, creamy white.
So, with this we should be able to evaluate genes, keep in mind though
that a series may contain four genes, but any individual dog may only have
two genes from each series.
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v
Red/black mask |
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The
A-series controls the development of patterns consisting of the DARK
(black/brown), and LIGHT (red/golden), coat colours
The A-gene is the most dominant in the series. It determine patterns from
the dark and light pigment. If the dog carries an A-gene, it will turn
black or black & white. If the dog carries an a-gene (opposite an
A),it
will be born darker than what it will be as an adult. It will also be
lighter underneath than on its back.
OBS-OBS!! Today
we know, that the dominant black genes are not in the A-series, but in a new
found K-series. Read these
Canadian
Site.
So something in my article down under are not right anymore!
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The
ay – gene is recessive relative to “A”, but dominant in relation to
the at – gene. The ay -gene is the gene determining how much of the dark
pigment will be in the coat, but can be covered up by the A, in which case
black dominates. The colour will be sable if the gene stems from ay or
at.
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dark red/sable |
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The
at -gene is the most recessive allele in the A-series, in a dubbel
dose it gives black & tan, but if the other gene is ay, the dog will be
sable, and only if the puppy is given the at-genet from both the sire and
dam will it become black & tan. This means that if you mate black & tan
with another black & tan, all the offspring will become black & tan,
unless modified by for example the parti-gene. In those cases the dog will
become tri-coloured but may also appear to be black & white. The dog can
also become pure red / crème / golden, if it receives the recessive e from
both parents, as ee in dubbel dose prevents the formation of dark pigment
in its coat. Even black or sable may produce black & tan, if both parents
carries the at –gene recessively.
A,ay and A,at will give black dogs, ay,at og ay,ay gives sable,
at,at gives
black & tan. You will likely never see totally black dogs after two sable
dogs, but the chance increases if the parents are in a pure color
providing at least one of those are offspring from a completely black dog
or a “pure” black & white parti.
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 v
Sable
Black/white parti |
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The
B-series have two alleles, and affects the color of the darker
pigment.The B-gene is the allele for black pigment in coat and snout,
B is
dominant towards b. The b-gene is the recessive allele for livercolour or
brown. A puppy will only become livercoloured or brown, if both parents
carries the b-gene. Earlier liver or brown was not wanted in Tibbies, but
is now approved as a colour variation.
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Chokolate/tan |
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The
C-series has four alleles, and affects the color of the lighter
pigment. C-gene is therefore the cause of the variations in the soble nuances, from
deep red and towards créme or white. C is dominant and gives a deep red or
golden colour in the lighter areas of the coat, if such exists.
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Wiethe
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The
cch–gene (Chinchilla-gene), is the second gene on the
dominant scale and reduces red and yellow, but has no effect on black.
This gene will be invisible on a black Tibbie. To the contrary it is the
gene which is relevant to create silver & sable, which in fact is a red &
sable dog where the red has gone pale due to the
cch-gene. The
ce
–gene
is
the most recessive gene in the series, giving an extreme, pale red. Even
if the dog has a dominant C-gene it will nevertheless give a considerable
bleaching of even very dark colours. The dog will with Ce, even if its
golden, become crème & white. In a double dose the ce ce becomes almost
albino. Nose and eye pigmentation is diluted and any black hair in the coat
will change towards a pale grey. ca -gene is the albino gene, where no
colour exists, not even on lips, nose or the edge of the eyelid. Even the
eye will be “redish” in a pure albino, because there is no pigment to
obscure the capillaries inside the eye itself. The surface of its skin
will be pink.
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Silver/sable
Silver / Sable |
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The
D-series has two alleles, affecting the darker areas in the coat (as
C controls the light pigment).
The D-gene is dominant, whilst the d-gene is recessive. D provides a deep,
concentrated pigment in hair, nose and in the irises of the eyes, whilst
d
contributes to ”blue”, which is actually a dilution of the pigment. A
completely black and a deep red Tibbie is probably examples of a DD or
Dd combination. I am not familiar with a “blue” Tibbie, whih typically
would be a dd, thus maybe D is only found as a homozygous chromosome in a
Tibbie?
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Red/sable Sable |
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The
E controls the production of dark pigment (liver or black).
The E-gene is the reason for seeing such a wide variety of colour patterns
in Tibbies. The genes E and A affects each other a great deal, therefore
it is hard to tell if a colour and/or pattern is caused by A or by
E.
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The
Em -gene is the most dominant, it spreads the dark pigment whereas
the pattern-gene, A, will order Em to carry this out. It is also thanks to
Em that many of our dogs have a dark mask.
A dark mask cannot be seen in a
black dog of course, but will be evident in a sable or black & tan. E
produces dark pigment ( as directed by A), without a mask. E is recessiv to
Em, but dominant to e. The e-gene is recessiv to both
Em and E. e cannot
produce dark pigment. Even if the A-gene for black is present, the dog
will not have dark or black hair, because the e-gene does not produce dark
pigment, which is required for A to work. All dogs having ee will become
pure red, golden, créme or white, regardless of other genes. Only a
particolor gene can be “visible” in this phenotype. On the other hand
i may appear completely black puppies from mating two golden/créme/sable
individuals, providing they have the genes ee-AA (creme / pale golden, as
e prevents the black from A), and ayay EE (sable), which will give the
puppy the gene-combination Aay – Ee. Because A is dominant realtive to
ay,
and E is dominant relative to e, the pattern-gene A
(pure black) may
benefit from Es’s production of pure black.
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Black Mask
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The
G determines if a color goes paler with age
The G-gene is dominant and becomes evident by the darker colours going
paler with age (the dog gets grayer). Darker colours do not go pale,
providing the dog does not carry the g-gene. The g–gene is recessive.
G
will nevertheless appear somewhat different, depending on the dogs
gene-pool, especially from some of the B and D – series of genes.
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Golden with black mask |
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The
S locus determines white patterns
S-gene is the most dominant gene and means the coat will be in one
colour.
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Golden without black or bl. mask |
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The
si –gene produces just small amounts of white and is recessive to
S. It is also called Irish Spotting, which means there are small amounts
of white on the paws or chest. sP
is the gene responsible for a typical particolor pattern, the majority
of the dog is white. Usually only about ¼ of the dog is coloured, but
due to the plus and minus factor that plays a part in the production of
pigment in this locus, it can be difficult to decide if the gene actually
is sP
or si. sP
is also called Piebald Spotting.
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Tricolour
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The
sW
–genet
is the most recessive gene. It produces extreme amounts
of white and quite often the dog only has small, coloured markings around
its eyes or on its head, ears or tail. sw will, in combination with S
or
si, give atypical particolor patterns. According to Ms. Catherine Marleys
article on Lhasa Apso, she writes that the sw--gene often appears together
with deafness in the inner ear (cochlea). I know of two cases like this in
Tibbies. But according to a Norwegian canine medical book called: ”Hund,
Avl og Helse” ( Dog, Breeding and Health ), written and published by the
association for veterinary practise on small animals, there are no
hereditary defects tied into this gene, but instead to the M-gene, which
in double doses can cause deafness and sometimes even blindness and
sterility. I have not been able to find out which source is correct.
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Particoloured with just
a litle colour on head |
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The
T-gene determines if spots appear = ”the ticking factor”
The T-gene is dominant and produces ”ticking”, more or less clearly
seen coloured spots inside white areas, and is produced by the S-gene.
These spots first become evident as the puppy gets somewhat older. The
t-gene is recessive and does not produce ”ticking”.
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ticking |
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Analysing colourgenes in your dog
A litter can tell a lot about your dogs genetic characteristica, which can
be of great help in your breeding program. |
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Catherine Marley writes (about Lhasa Apso): ”I mated a sable
dam with a
red & sable sire. Of seven offspring three was black & tan, three was sable
and one was a clear golden. From this I can deduce:
1.Both parents are sable, thus they must
have ay and an E.
2.Since I had atat and ee - puppies, both parents must also carry
at and
e.
3.There was noe blue or diluted créme puppies, meaning the parents must
each carry at least one C and one D. The male is deep red, and should
therefore be CC. The dam is somewhat lighter therefore more than likely
a Ccch.
4.There was no particolour puppy thus S or si must be present in both the
parents.
5.The dam is greyish, so she must have at least one G. The sire is not
greyish and is therefore gg.
6.The sire has produced brown noses before but not in this litter, which
makes it certain it is a Bb. As there where no brown snouts in the litter
it must mean that the dam, possibly, is a BB.
When putting all these factors together I am
able to work out a complete list for both the parents and theyr offspring.
- sire:
ay at Bb, C(C?), D(?), Ee, gg, S(si)
- dam: ay
at, B(B?), Ccch, D(?), Ee, G(?), S(si)
When I am mating this dam again, I can avoid black & tan puppies by
mating her with a sire that never has produced black & tan, not even when he
has mated with a black & tan dam. (This "proves" that he was homozygous in
relation to ay ay and that he did not carry at gene.)
To avoid pure coloured puppies I had to find a sire that had been mated with a
pure coloured dam that had never produced pure colour puppies. This way I
can be sure that my dam will not carry livercolour recessively and I can
therefore mate her with known carriers of livercolour without giving a
thought to having livercoloured puppies.
If you feel this type of analyses is somewhat technical feel free to use any
of the following descriptions concerning colour breeding.
1.
If two animals with identical, recessive patterns are mated, the result
will be the same: Black & Tan x Black & Tan = Black & Tan. Unless they
carry e, that in double dose prevents the formation of black pigment.
If they carries parti, the puppies can be tricolour.
2.
Recessive, white spots in a massive and extreme version, can cover all
patterns. Pure golden recessive (ee), can cover all A-series patterns
(pure colour, sable and black & tan), you will never know what a pure
colour golden carries in relation to the dark pigment patterns, unless you
test your breed in a laboratory.
3.
A black & tan with a deep and well developed “tan”- pattern, will produce
a large portion of good red puppies, when mated with a sable.
4.
A pure and true black will produce black regardless no matter who it mates
with.
5.
Two red & sable can produce any colour except pure black.
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