AMBER AND RUSSET - LATE COLOUR CHANGE GENES Copyright 2014, Sarah Hartwell
The
ancestors of the
domestic cat were nondescript
black /
brown striped
tabbies. Over the
centuries , mutation produced a
wide array of
colours based on 2
different pigments. Eumelanin gives the blacks,
browns and
blues while phaeomelanin gives the reds, fawns and creams.
A few
other genes give
further variations on those colours
such silvers, colourpoints and solids/selfs. Mutations
continue to
occur and unexpected colours also
turn up due to inbreeding where recessive
genes,
hidden for generations, start showing up.
AMBER
AND LIGHT AMBER During the
1990s , some purebred
Norwegian Forest Cats in
Sweden produced
chocolate /lilac and
cinnamon /fawn offspring.
However , those colours
are not
found in the purebred Norwegian Forest Cat gene pool. Had the
gene pool become polluted by
someone ,
perhaps generations ago,
breeding their Norwegian Forest Cat to
another breed? Was it a
spontaneous mutation?
Crossing of those cats with
known chocolate and
cinnamon colour cats of other breeds ruled out chocolate/lilac and
cinnamon/fawn genes.
These cats were a totally new colour, peculiar
to the Norwegian Forest Cat gene pool and dubbed the "X
Colours". They are now called Amber and Light Amber. The Amber
effect is due to the extension gene (also called red
factor ) which
controls the
production of red and black
pigment . The
dominant version of the gene produces normal black pigment in the
coat while
the recessive version produces red pigment. The name
comes from the
effect of black or brown pigment not being
extended throughout the
whole coat, but being restricted to the
skin of the extremities and
to the
eyes (for example in bay
horses ).
This
Norwegian Forest Cat was bred by Yve Hamilton Bruce from a
silver mackerel tabby
female (imported from Denmark) and a
classic red tabby
and white
male . The
result was 1 silver tabbies and 2 silver tabbies
with white. At just over 3 months old, this silver and white tabby
male
developed a large
patch of
bright red
hair on his
back which
continued to
spread . Eventually the whole fur will become amber. The
effect of amber during the colour-change stage depends on the
original colour -
solid black or
blue , bicolour or tabby. The cat
pictured is not a
typical amber as it has the silver gene so the
amber effect is overlaid on silver.
A
non-agouti amber Norwegian forest Cat resembles a silver tabby, but
has a distinctive black
nose and black paw-pads instead of the
pink /reddish nose with black outlining found on conventional silver
tabbies. The
photo below shows a non-agouti amber. According to Rui
Pacheco,
although this cat is
clearly non-agouti because of the black
nose, he has the
phenotype of a silver shaded. Rui's theory is that
the amber gene invalidates the
action on the non-agouti gene;
wide-banding will further lighten the
base colour
giving a very
pale cat with black nose and paws. Amber cats are basically black cats
with a colour modifier that affects the deposition of pigment on the
hair shaft, but not the skin colour. That is why in non-agouti cats
the nose remains black and in agouti cats it remains pink.
PLATINUM
The
platinum effect is found in some lines of Silver Persian/Chinchilla
Longhair. In 1986/7, Cheryl Bennett
reported in The Silver and
Golden Persian Newsletter (ACFA) that one of her shaded silver females
(Kelley
Lane Contessa of WeANDE) had changed from
pure silver to pale
golden. Contessa’s
parents were a shaded golden and a shaded
silver; these were
full siblings. At 10 – 12 months of age,
Contessa began to “tarnish” i.e. show
cream /reddish patches and
by 3
years of age she was entirely pale golden. She produced a number
of Silver Persians
without tarnish, but she failed to produce any
offspring when mated to a golden
sire . One of Contessa’s male
offspring turned from silver to golden as an
adult . An adult Silver
Persian from
England (Lynchard Silver Shadow) was exported to
Australia and also turned golden. Shadow had a few golden hairs on
his paw, but did not turn golden
until he was a
year old when his
coat turned to pale beige. By 3 years old he was entirely pale
golden. Shadow was bred to a genetically golden female, but the
pairing only produced silver offspring. However, at
least one of his
silver offspring
later turned pale golden. Other descendents of
Contessa also
went through the late colour change. During the 1980s,
several other breeders of Shaded Silver and Chinchilla Persians
came forward to
report that their cats had developed reddish, brownish or
golden-coloured fur
along their spines as they
aged . Many of the cats
had no golden in their ancestry. At
first it was dismissed as an
unavoidable genetic
fault where silver was incompletely dominant and
did not hide the recessive golden colour.
A
common ancestor of all the colour-
changing Silver Persians was a
stud cat called Kelly Lane Andromeda (in the UK)
whose descendents were
exported to the USA in the 1950s and
1960s . Some of those descendents
were influential stud cats and would have spread the mutant gene far
and wide. Controlled inbreeding (linebreeding) helped establish the
gene, which would later
double up to produce colour-changing Silver
Persians. The effect of this gene on Golden Persians, if indeed it
has any effect, is not known.
Except
for red-silvers and cream-silvers, silver cats should entirely
lack phaeomelanin (red or cream pigment) and only have eumelanin (black,
brown, blue etc)
present . Perhaps some other gene
causes the
eumelanin structure to change so that it is
perceived as a golden
colour. Chemical
analysis proved that the late colour change Silver
Persians did not have phaeomelanin pigment present.
AMBER-TYPE
EFFECT IN MANX
An
amber-type effect has also been
seen in a Manx cat. Janet McArthur
bred a male Manx (a longy i.e. with
tail ) that was born an ordinary
black/brown mackerel tabby without much rufousing, as was his
sister .
In
addition , the male had white ticking at the
tips of his hair. As
the male grew, his stripes
faded out and
became spots while the black
markings also changed from black to a burnt red-brown colour and his
white ticking became smaller. The change from
stripe to spots was
probably an optical effect caused by the change from black to
red-brown. His dorsal line became a burnt golden brown, and the
background colour was
similar to a washed out sorrel colour (sorrel
is a colour found in Abyssinians).
There are a few oddities in his ancestry. His
mother ,
Pearl , was a black
Manx and his sire was a normal black/brown tabby from the
same black
Manx mother. The inbreeding was
accidental , and may have
brought out
a recessive gene. Pearl was born to a black/red tortie (carrying
dilute and colourpoint) and a red van-pattern sire; this pairing
should not produce solid black females so, barring an anomaly in her
sire's germ line, Pearl may be a tortie where the red has not been
expressed in the coat. Pearl has also produced a
kitten that changed
from black with white ticking at the hair-tips, to black
smoke and
then to solid black without ticking.
BIMETALLIC
/ SUNSHINE
The
informal
term "bimetallic" (referring to a mix of silver
and golden or silver-gilt) describes some Siberian silver tabbies
that turn golden in a
rather patchy fashion. Unlike the amber gene,
the colour change does not start on the back and
work downwards, but
seems distributed throughout the coat. The
formal name "sunshine"
has been proposed for this
emerging gene.
RUSSET
Similar
to amber is russet, which turned up in a line of seal (brown)
European-style Burmese in New
Zealand in 2007. It has subsequently
occurred found in the
related Mandalay (similar to the
Asian in
Europe ) and
appears to be a mutation of the extension gene. The first
known russet was a pure-bred Burmese called “Molly” in 2007.
There is now an experimental
programme in NZ to breed Russet Burmese
and to investigate dilute russet, russet tabby and solid russet (as
opposed to the Burmese sepia form of russet).
The
first russet kitten “Molly” was born an "odd-coloured lilac
(lavender)" which gradually lightened as she grew, progressing
through lilac-caramel and chocolate
ticked tabby and then
dramatically changing to red. Chocolate ticked tabby and red were
both impossible from her pedigree, and in any
case , reds are not born
as chocolate tabbies! Several more unusually coloured kittens were
born in different litters and all went through the same
colour/pattern
changes . The ancestors of these kittens were seal
Burmese and had no silver, tabby or Mandalay (Asian)
blood . The
pedigree had both dilute and chocolate, there were no reds, creams or
torties until 4 generations back. DNA
testing showed some kittens to
be genetically seal and other genetically chocolate.
Hence the new
colour is due to a different mutation currently known as russet.
Russet appears to be due to a recessive mutation that causes black
pigment (eumelanin) to gradually
fade to a
minimal amount while
leaving red pigment (phaeomelanin)unaffected.
Russet
kittens resemble tabbies at
birth , but have pink noses and paw-pads,
pale fur
around the pads and genitalia and a pale tail-tip - all of
which would be
dark in tabbies. The muzzle and fur around the eye is
ivory. The back is solidly dark rather
than ticked, becoming pale
ivory halfway down the flanks. The back becomes more ticked
appearance,
almost a saddle, as kittens undergo the colour change and
the
face becomes reddish. By age two, they may resemble a red
Burmese. It differs from amber as ambers have dark noses and
paw-pads. Non-agouti (solid) amber kittens are very dark with a dark
face that is last to go red while russet kittens have off-white faces
(possible due to Burmese sepia gene in the mix), which are the first
part to go red (rather than the last as in ambers), and pale
undersides. The russet colour change appears to be slower than the
amber colour change. Russet kittens to
date have been larger at birth
than their siblings and somewhat on the large side as adults.
RECESSIVE
BROWN - THE ENIGMATIC BARRINGTON BROWN GENECopyright
2010 Sarah HartwellThis
page pulls together what is known about Don
Shaw 's Barrington Brown
gene, a form of recessive brown/colour dilution only reliably
recorded in a
colony of
laboratory cats,
none of which are believed
to have
left the laboratory. To make this comprehensible to the
non-genetics
expert I have
referred to "copies of genes" or
"versions" of genes although the
correct terminology is
"alleles". There is also a brief guide to Shaw's
terminology at the end as Shaw's writing pre-dated modern "standard"
symbols and terminology.
Don
Shaw was an
early feline geneticist in the USA. During the 1950s and
1960s, there was no standard form of genetic coding and Shaw used his
own system of genetic coding which can be difficult to read
today . He
also referred to chocolate, which is a mutation of the black gene, as
"chocolate dilution". What modern fanciers
call dilution,
Shaw called "maltesing" (Maltese i.e. blue cats were a
genuine dilution of black). Shaw viewed dilution as being due to the
reducing amount of melanin present in the hair and not by the way
pigment
forms clumps in the hair. Chocolate had less melanin than
black,
therefore Shaw called this dilution. Blue has a the same
amount of melanin, but arranged differently, so Shaw did not
consider this dilution.
In
simple terms , the black (eumelanin) colours in cats is due to a
series of genes (alleles to be precise) with the
following order of
dominance/recessive (most dominant at the top, most recessive at the
bottom ). The
chart also shows how these combine with dilution genes
and dilution modifier genes. A cat inherits 2 copies of the black
gene and only the more dominant version will show up while the
recessive gene will be hidden. The caramel form only shows up in cats
that
already have the dilute colour and it lightens and adds a
brownish
cast to the dilute colour.
ORIGINAL COLOUR DILUTE VERSION CARAMEL VERSION OF THE DILUTE VERSION (DILUTE MODIFIER, DOUBLE DILUTION) Black
Blue
Caramel (UK: Blue-based caramel)
Chocolate
Lavender (Lilac)
Taupe (UK: Lilac-based caramel)
Cinnamon
Fawn
UK: Fawn-based Caramel
These
colours will naturally
look a
little different on Burmese (due to the
sepia gene), Tonkinese (
mink gene) and cats with the silver Inhibitor
gene. For clarity, this article will
ignore those additional genes
and just look at the eumelanin (black) series of colours.
An
additional type of recessively carried brown colour has been reported
in laboratory cats, but not in the
outside world. Termed "Barrington
Brown", a cat with two copies of this gene had black pigment
diluted as shown below. Because it hasn't (yet) been seen in the cat
fancy , this gene is enigmatic to many fanciers.
Some
have suggested it is the same as caramel (dilute modifier), however
some reports indicate cats with 2 copies of the Barrington Brown gene
were different in colour from cats with only one
copy of the gene
(which seems odd
since the gene is recessive and cats with only one
copy should have dilution at all). When 2 copies were present,
Barrington Brown had an additive effect on black and chocolate, and
presumably on cinnamon (which may have been unfamiliar to Shaw).
ORIGINAL COLOUR BARRINGTON BROWN DILUTION Black
Deep mahogany brown
Chocolate
Light brown
Cinnamon
Cafe -au-
lait (
milk coffee colour)
The
dilution only happens if 2 copies of Barrington Brown are present,
although some
sources suggest the genes had additive effect on each
other to create the pale milk coffee coloured cats when there were 2
Barrington Brown genes. Since Barrington Brown is a recessive gene.
If only one copy was present it should be masked by the dominant
non-Barrington copy. This is part of the problem when interpreting
reports that use an old, non-standard genetics notation!
ba - Barrington Brown Locus (unverified) Genotype Description Phenotype Ba/Ba
Homozygous - Non Barrington Brown
Cat unaffected - i.e. Black/Brown/Chocolate etc
Ba/ba
Heterozygous - Non Barrington Brown - carrying Barrington Brown
Cat unaffected - i.e. Black/Brown/Chocolate etc
ba/ba
Homozygous - Barrington Brown -
liberty of renaming
Mahogany Brown/Light Brown/milk coffee in colour (depending on whether cat is black/chocolate/cinnamon)
In
the 1960s, chocolate was
described as a dilution of black and the
third possible version of the gene, cinnamon, was apparently
unfamiliar to Shaw (or not
reflected in his terminology). Shaw’s
Barrington Brown article was first written in the 1960’s in the
Journal of Cat Genetics, and reprinted in the early 1970’s in Cats
Magazine and has been
subject to much reinterpretation, especially
when a dilute modifier emerged in the cat fancy.
According
to Shaw's breeding data, Barrington Brown (mahogany brown) dilution
was inherited in much the same way as “standard chocolate dilution"
(black/chocolate alleles) by reducing the amount of pigment in the
hair and by producing elliptical pigment granules instead of
round granules. Elliptical pigment granules refract light differently and
give a reddish-brown colour instead of black/sepia. In Shaw's
terminology which can confuse modern readers, chocolate is a dilute
of black (while blue is "maltesing" of black).
It
became apparent that Barrington dilution gene was in a different
location to the ordinary black/chocolate genes and was inherited
independently of black/chocolate. That
means it wasn't the modern
cinnamon. Genes in different locations can
affect different enzymes
involved in production of the same protein, in this case the
production of eumelanin pigment. Shaw referred to the “standard
chocolate dilution" as affecting
enzyme D while the Barrington
system
affected enzyme B. He identified Barrington Brown as
having 2
alleles; the dominant
wild type and the recessive Barrington Brown
dilution.
B+
= Wild type gene. Apparently
responsible for normal Enzyme B
production, giving full intensity of melanin.
b = Barrington Brown
recessive gene. When 2 copies are present there is less Enzyme B
produced which means less melanin produced; the pigment granules are
elliptical (reddish-brown) instead of round (black).
He
gave it the name Barrington Dilution or Barrington Brown because it
was
discovered at the Quaker Oats Nutritional Laboratories in
Barrington, Illinois. The first cat known to be homozygous for
Barrington Brown was born at the Barrington Laboratories. This was a
strangely colored light brown (
rich caramel or perhaps cafe-au-lait)
male kitten homozygous for Barrington Brown as well as having
“standard chocolate dilution". The 2 gene systems were
additive in
nature and each expresses its effect as if the other were
not present i.e. the end result is the sum of both Barrington Brown
and "standard chocolate dilution" being expressed. Shaw's
description of "rich caramel" (light tan) misled 1970s
breeders to believe the emerging dilute modifier was the same as
Barrington Brown.
Don
Shaw and Wayne Durdle investigated this gene in depth. Cats carrying
the Barrington gene were donated by the Quaker Oats Nutritional
Laboratory to the Feline Research Laboratory at Tuskegee Institute,
Alabama (maintained there from
summer 1966 to mid-1969). No
Barrington Brown carriers were believed to
exist outside of the
colonies and Barrington and Tuskegee.
Studies established that the
light tan or cafe-au-lait colouration was due to the combined
effects of "standard chocolate dilution" and their Barrington Brown
gene.
Shaw
had left the
project in July 1968 and Durdle reportedly terminated
the colony in
June 1969 (this suggests the cats were destroyed,
neutered or used in other research). To their
knowledge - and to the
ongoing chagrin of many breeders - the Barrington Brown cats had no
direct descendents in the cat fancy and the gene was
lost . However,
Shaw noted that some "doubly diluted" kittens were
appearing in the cat fancy. These had no apparent connection to the
Barrington or Tuskegee cats. He also mentioned unconfirmed reports of
a dilution system similar to the “standard chocolate dilution"
but not traceable to any known chocolate ancestry.
Shaw
offered the following possibilities:
- a leak of the Barrington Brown gene from one or other of the laboratory colonies into the cat fancy population; perhaps some cats or kittens had been taken home as pets and bred.
- a new mutation in a completely different gene location
- a new mutation at the same location as his Barrington Brown gene
- an independent recurrence of the Barrington Brown mutation.
To
identify the
relationship , if any
between the Barrington Brown cats
and those with "double dilution" would
require test-matings
between the new "doubly diluted" cats and some known
Barrington Brown cats. Since there were no known Barrington Brown
cats outside of the laboratory and the lab colony had been
terminated, this wasn't possible. In the 1970s, Pat
Turner stated ,
without any supporting
evidence , that caramel (the double dilution
mentioned by Shaw) was the same as Barrington Brown. The dilute
modifier (caramel) colours are not the same as the colours described
by Shaw, though some websites continue to repeat Turner's
claim that
Shaw called the caramel colour Barrington Brown. Turner had simply
jumped to conclusions. Barrington Brown
cannot be the same as caramel
because Barrington Brown affected black and chocolate, but caramel
only affects blue, lilac and cream.
Shaw
noted that recessive
traits emerge in pedigree cats because of
line-breeding and inbreeding which matches together genetically
similar individuals. This means a better
chance of cats inheriting 2
recessive versions of a gene and new traits showing up as result -
just as they did in the Barrington colony of cats.
From
a breeder viewpoint, it is sad that "recessive brown" has
been lost. Shaw's descriptions indicate that it wasn't the same as
caramel. Its effects on the wider palette of feline colours -
torties, ticked and patterned tabbies, Burmese sepias, minks and
colourpoints - can only be hypothesised. From time to time there are
reports of odd colours in cats,
including a tantalising "palomino"
described as "the colour of a brown
paper grocery bag" from
the USA that might just have been the light tan noted by Shaw.
SHAW'S
TERMINOLOGYModern
feline geneticists use b/b for chocolate, but Shaw defined chocolate
as d/d, because to him it was a dilution of black.
Reading Shaw's
work on black, chocolate and Barrington Brown without knowing his
terminology is therefore confusing. In Shaw's defence, the standard
gene symbols had not been defined in the 1950s and 1960s.
Light
tan/cafe-au-lait in Shaw's terminology is d/d, b/b. To a modern
reader, d/d, b/b indicates lilac. This, as much as any
visual similarity, helps
explain why his Barrington Brown is so often
confused with the dilute modifier.
Shaw’s
Chocolate alleles
D+-
= Normal colour (black/sepia)
d/d = chocolate (in Shaw’ s
words ,
Chocolate Dilution)
Shaw’s
Maltese alleles
M+
=
Dense colours e.g. black
m/m = Maltese (or in our terms
dilution) e.g. blue is the maltese of black
Shaw's
Barrington Brown
allele B+
= Normal coat
b/b = Barrington Brown
Lilac
(in Shaw's terminology) would be d/d, m/m = Dilution allele
(chocolate) + Maltese allele = lilac.
Lilac in modern
terminology is b/b, d/d = Chocolate allele + dilution allele = lilac.
Although
there is no
official modern
symbol for the lost Barrington Brown, Ba
is often used for convenience in modern discussion (since it isn't
allocated to
anything else ).
Brown
Locus (modern symbols)
B/-
= Black/Brown (Shaw's black/sepia)
b/b = chocolate (Shaw's
"standard chocolate dilution")
bI/bl = cinnamon
(probably not recognised by Shaw)
Barrington
Brown Locus (modern symbols)
Ba/Ba
- no Barrington Brown dilution
ba/ba - Barrington Brown
dilution/recessive brown
THE BASIC SELF (SOLID) COLOURS OF CATSCopyright
2002 - 2013
Sarah
HartwellGenetically
speaking, there are
four basic self (or solid) colours of cats:
black, chocolate, cinnamon and red. All other self colours are
modifications of these. Although covered
here as a self colour, red
is a form of tabby and it is impossible to completely eliminate the
tabby markings. Why are there not
five basic colours? White is
counted as an absence of colour rather than a colour.
Different
countries, registries and breeds have different
names for some of the
same basic colours.
Even where the same name is used, there may be
different
views on what is an acceptable or
ideal version of that
colour. Colours which appear identical to the human eye are caused by
different genetic interactions.
The
same colours are called by different names in different breeds. Even
in the same breed, the colour may have different names depending on
which
country the cat comes from and which registry it is registered
with. American registries like to add "mink" after the
Tonkinese colours whereas
British registries use the same name for
that colour as is used in the
equivalent Siamese or Burmese colour.
Confused? Don't worry - there are some
cross -
reference tables later
on!
The
jet-black colour you known as "black" is called "
ebony "
and "ebony tabby" in Orientals, "black" in solid
coloured domestic shorthairs, "brown" when it refers to
brown tabby domestic shorthairs, "bronze" in Egyptian Maus,
"tawny" in Ocicats and "ruddy" in Abyssinians. In
colour-pointed cats, "black" is called "seal". In
Burmese it is "
sable " or "seal sepia" and in
American Tonkinese it is "cinnamon" or "natural mink".
In the Asian breed (self Burmese cats) it has a breed name to itself
"Bombay". Shaded silvers, black smokes and chinchilla cats
may look various shades of
grey or silver, but they are black cats
with silver
roots to their fur. Add dilution and it becomes "blue".
Modify the dilution and it becomes "caramel". Yet it is
still basically a black cat.
WHY
RED SELF CATS ARE STILL RED TABBIESStrange as it may
seem , all red cats are actually red tabby because the
non-agouti gene (the gene that turns a tabby into a self/solid
colour) does not affect the way red pigment is deposited. A variety
of other genes, called polygenes or modifiers,
control the intensity
of colour and
contrast between markings and background colour.
Selective breeding has reduced the tabby markings to produce a cat
that
looks solid red by breeding from those cats with the least red
markings (cats with "low contrast" between markings and
background colour). Because the non-agouti gene does not work on the
red pigment, red tabby
ghost markings can
never be completely
eliminated and may be seen on the tail,
legs and
forehead and as a
darker
region along the
spine . Even though red cats are registered as
"red self" they are still red tabbies, albeit red tabbies
with very reduced markings. Because they lack the polygenes for high
contrast between markings and background colour, their offspring also
appear to be red self. More information can be found in
Robinson 's
"Genetics for Cat Breeders".
DILUTION
AND MODIFIED DILUTION - MALTESING AND CARAMELISINGThe
simplest modification of the 4 basic colours is dilution. As the name
suggests, this "washes out" the original colour to
something paler. This is also called maltesing since the it was first
identified in black cats and blue cats - Maltese is term for
blue-grey and some of the eary blue cats imported into
Britain were
known as Maltese cats.
A
secondary type of dilution is called the dilute modifier. It only
affects already diluted colours. Since it gave
rise to the colour
"caramel". I have referred to it here as "caramelising"
purely to
avoid confusing the layperson. Textbooks always
refer to it
as the dilute modifier.
ORIGINAL COLOUR DILUTE VERSION CARAMELISED VERSION OF THE DILUTE VERSION (DILUTE MODIFIER, DOUBLE DILUTION) White
N/A
N/A
Black
Blue
Caramel (UK: Blue-based caramel)
Chocolate
Lavender (Lilac)
Taupe (UK: Lilac-based caramel)
Cinnamon
Fawn
UK: Fawn-based Caramel
Red
Cream
Apricot Amber
Light Amber
Black,
chocolate and cinnamon are all versions of the same gene. With the
exception of "red" which is a
special case, genes are
inherited in pairs - one from each
parent . Some genes are dominant
over
others and only the dominant one will be expressed (show up).
The other gene (the recessive) will still be lurking in the
background and can be
passed on to offspring. Depending on which
pairing a cat inherits, it will be one of those basic colours. The
fact that at it may look different depends on many other genes which
alter the way in which these three basic colours are expressed.
If
it inherits black + black OR black + chocolate OR black + cinnamon it
will be black.
If it inherits the dilution gene it will be
blue.
If it inherits the dilution gene AND the caramelising gene
it will be caramel.
If
it inherits chocolate + chocolate OR chocolate + cinnamon it will be
chocolate.
If it inherits the dilution gene it will be
lavender.
If it inherits the dilution gene AND the caramelising
gene it will be taupe.
If
it inherits cinnamon + cinnamon it will be cinnamon in colour.
If
it inherits the dilution gene it will be fawn.
If it inherits the
dilution gene AND the caramelising gene it will be a pink-brown..
Many
early caramels were probably registered as fawns or lilacs, probably
as
poor quality individuals. The colour
differences are subtle enough
that it may be necessary to check what is in a cat's pedigree to work
out the exact colour. To the
rest of us, such cats are simply
"biscuit colour" and are no less attractive for it!
Red
is a different gene to black, chocolate and cinnamon. It is a
sex-
linked gene which means a female must inherit 2 copies of the red
gene in order to show up as a red cat. A male only
needs one copy of
the red gene to be a red cat. This is why
ginger tomcats are more
common than ginger females (though contrary to
popular belief , ginger
females are neither
rare nor infertile!). If a female only inherits
one red gene, she is a tortoiseshell.
If
a female inherits red + red she will be red (ginger).
If she
inherits 1 red gene she will be tortoiseshell (red/black,
red/chocolate or red/cinnamon depending on the other genes
present)
If she inherits red + red AND the dilution gene she will
be cream.
If she inherits 1 red gene AND dilution gene she will be
dilute tortoiseshell (blue/cream, lilac/cream or fawn/cream)
If
she inherits red + red AND the dilution AND the caramelising gene she
will be apricot.
If she inherits 1 red gene AND dilution gene AND
the caramelising gene she will be dilute tortoiseshell in the
caramelised range of colours (though this may not show up very well
and may be impossible to identify.)
If
a male inherits 1 red gene he will be red.
If he inherits 1 red
gene AND dilution gene he will be cream.
If he inherits 1 red gene
AND dilution gene AND caramelising gene he will be apricot.
In
reds, there are genes for rufism i.e. for the depth of the red
colour. This is why show-quality reds are a rich, deep red colour
while alley cats are more often marmalade or ginger. Early reds
(1880s) were known as yellows; the depth of colour was
improved over
many generations of selective breeding.
In
1924, a series of breeding experiments between a Siamese female and a
tabby male resulted in black offspring that themselves produced tabby
offspring. This suggests a gene for black that is dominant to tabby,
the opposite of the known behaviour of tabby and black! It is
possible that the Siamese female, one of a
pair imported from
Bangkok , had a mutation for black colour that was dominant instead of
recessive. There have been no further reports of dominant black in
the cat population. Dominant black is genetically different to the
black colour described
above , but
unless it occurs
again its
interaction with other genes will
remain unknown.
Note :
The usual explanation of black (B), brown/chocolate (b) and cinnamon
(bl) is that there are 3 alleles of the black locus gene. Chocolate
carrying cinnamon can appear as light chocolate in some breeds, but
basically there are 3 phenotypes: black, brown/chocolate and
cinnamon. An alternative explanation suggests 2 gene loci, each with
two alleles. One locus is black/brown. The other locus is a modifer
that, when homozygous (2 copies are present), changes black to
cinnamon and brown to pale cinnamon. This gives 4 phenotypes: black,
brown/chocolate, dark cinnamon/light chocolate and light cinnamon.An
additional type of recessively carried brown colour was reported in
laboratory cats in the USA in the 1960s, but not in the outside
world. Termed "Barrington Brown", a cat with two copies of
this gene has black diluted to deep mahogany brown, chocolate dilutes
to light brown and cinnamon dilutes to a pale cafe-au-lait. There are
suggestions it may have been the caramel gene, but the descriptions
of the colours
quite different. The confusion seems to stem from the
discovering describing the light tan of the Barrington Brown cats as
"caramel coloured". Barrington Brown cannot be the same as
caramel because Barrington Brown affected black and chocolate, but
caramel only affects blue, lilac and cream.
CARAMELThe
Dilute Modifier gene was posited by Patricia Turner who erroneously
believed it to be the same as the Barrington Brown gene reported in a
colony of laboratory cats. In essence, caramel lightens and gives a
brownish cast to the underlying colour. How can
adding brown make
something lighter? Brown (in terms of colour, not genetics) comes in
a variety of shades ranging from fawn to chocolate and adding a
brownish hue is not the same as mixing
paint . With the dilute
modifier, blue becomes caramel, lilac becomes taupe (brownish grey)
and red becomes apricot. In
practice , these colours may only be
visually distinguishable from each other by knowing the cat's
genetics. Some
find caramel cats resemble golden series cats and
suggest that a theoretical hypostatic (hidden) silver/golden gene is
showing through, especially in the lighter colours where there is
nothing to
mask a hidden silver/golden colour.
In
the past, the Dilute Modifier has also been called “double
dilution” and “caramelising”. Some people are still not
convinced about caramel because almost identical colours can result
from blue + caramel and from lavender/lilac + caramel. With a
modifier gene, it is possible to get the same end colour (visually)
from 2 different base colours (genetically). It depends on what the
Dm gene is modifying (the expression of a protein) which is different
from mixing paint. Two different original proteins (relating to
melanin production or deposition)
could be modified by such a gene to
produce almost identical expression.
EXTENSION
GENES (BLACK MODIFIER) - AMBER/LIGHT AMBER AND RUSSETThe
Extension gene (formerly the Black Modifier gene) brightens black
areas of the coat. At birth, kittens appear to be black or blue (it
has not been found in combination with other genes recessive to
black), but become brighter as they grow. The Black Modifier has so
far only been
observed in the Norwegian Forest Cat. Recognition of
the colour by registries will
allow the cats to be correctly
registered and distinguish
them from chocolate, lilac, cinnamon and
fawn (not found in Norwegian Forest Cats).
COLOUR WITH EXTENSION GENE/BLACK MODIFIER Black
Amber
Blue
Light Amber
Chocolate
Lilac
Cinnamon
Fawn
During
the 1990s, some purebred Norwegian Forest Cats in
Sweden produced
chocolate/lilac and cinnamon/fawn offspring. Because these colours
are not recognised (they indicate outcrossing) they were called
"x-colours". Crossing a "cinnamon spotted"
x-colour with a fawn
Somali produced blacks and blues, not fawns.
Some x-colour cats were registered as "golden", but the
x-colour can be found in combination with silver (x-colour silver
tabbies), ruling out golden: a cat can be either silver or golden,
but not both. The offspring of an x-colour "cinnamon spotted"
and a chocolate point Birman were black and blue tabbies, ruling out
the recessive chocolate, lilac, cinnamon or fawn and ruling out a
recessive masking factor (i.e. that found in colourpoint cats). To
produce black and blue offspring, the x-colour must be genetically
black (dominant to chocolate). Further test-matings upheld these
conclusions.
Self
(solid) x-colour cats were born as poorly coloured black-silver or
blue-silver tabbies. Their tabby ghost-markings faded as they matured
and the colour became bright apricot to cinnamon colour with dark
brown paw pads and nose
leather with no black rim (a black rim is
characteristic of silvers). Mating a self x-colour cat to a
black-and-white and mating two self x-coloured cats together showed
that the colours were not agouti (not ticked), but were new colours,
now called Amber and Light Amber. Kittens are born dark and undergo a
period of
extreme brightening of the black/blue areas as they mature.
Their original birth colour is often seen only on the back and tail,
allowing amber and light amber to be distinguished from one another.
Amber
is apricot-to-cinnamon colour with brown paw pads, nose leather and
eye rims. Kittens are born dark or black, with ghost markings, and
brighten as they mature. Light Amber is a pale beige colour. Kittens
are born blue and brighten with age, becoming pink-beige to fawn at
maturity. The nose leather, eye rims and paw pads are dark blue grey.
(To
complete the description of amber/light amber: Amber Tabbies are
born apricot with black markings; the markings brighten to
reddish-brown/cinnamon at maturity. The nose is pink and the paw pads
and eye rims are brown. Light Amber Tabbies are born beige with blue
tabby markings; the markings brighten to pink-beige/fawn at maturity.
The nose is pink and the eye rims and paw pads are blue-grey.
Amber/light amber replaces black/blue in torties. Amber also occurs
with silver and in bicolours/tabbies -and-white.)
The
provisionally
named Russet Burmese is an experimental Burmese colour
in New Zealand. In 2007, Nicki and Bob Mackenzie's line of seal
(brown) Burmese (carrying dilute and chocolate) produced
"odd-coloured lilac" kittens which gradually lightened as
they grew, progressing through chocolate ticked tabby to red. The
kittens traced to the same
father and two related females (mother and
daughter ) and all three shared a common ancestress only a few
generations back. DNA testing showed the russet kittens to have the
standard seal or standard chocolate genes,
meaning there is an a
different gene causing the colour change. Russet kittens also tended
to be larger than their littermates, both at birth and as adults.
Russet appears to be a recessive gene from a spontaneous mutation. It
causes the black pigment (eumelanin) to gradually fade to almost
nothing while leaving the red pigment (phaeomelanin) unaffected. Like
the amber colour change, it might be an extension gene mutation.
Russet
kittens have pink noses and paw-pads and a pale tail-tip. The muzzle
and fur aroundthe eye is ivory. The back is solidly dark rather than
ticked, becoming pale ivory halfway down the flanks. The back becomes
more ticked appearance as kittens undergo the colour change and the
face becomes reddish. By age two, they may resemble a red Burmese. It
differes from amber (in Norwegian forest Cats) as ambers have dark
noses and paw-pads. Non-agouti (solid) amber kittens are very dark
with a dark face that is last to go red while russet kittens have
off-white faces (possible due to Burmese sepia gene in the mix),
which are the first part to go red, and pale undersides. The russet
colour change appears to be slower than the amber colour change.
PINK- EYED DILUTIONThe
type of dilution seen in cats is blue dilution (it dilutes black to
blue). A second type of dilution seen in many
mammals is "pink-eyed
dilution". Pink-eyed dilution is characterised by a pink or
ruby glimmer to the eye (depigmentation). The coat colour is often diluted
to bluish-fawn and the pink-eyed dilution factor is generally
inherited as a recessive gene. A possible pink-eyed dilute female cat
was reported in 1961. She was described as pink-eyed with a light tan
coat. She was mated to a chocolate point Siamese and produced three
tabby kittens 10
days premature. Sadly none of the kittens survived.
The colour of the kittens implies that pink-eyed dilution in cats is
inherited as a recessive
trait and is independent of the colourpoint
genes. The pigment granules in the hairs of pink-eyed dilute cats
were very small and yellowish brown,instead of the normal dark-brown
or black. (
Todd NB: A pink-eyed dilution in the cat. JHered 52:202,
1961.27.)
ALBINO,
DOMINANT WHITE, WHITE SPOTTING Albino
is generally
thought of as pure white, but the situation in cats is
more
complex . There are five known alleles for
albinism : blue-eyed
albino, pink-eyed albino, Burmese pattern, Siamese pattern and full
colour (non-albino). Full colour is dominant to all of the other four
alleles. Burmese pattern is incompletely dominant to Siamese pattern;
cats that inherit one of each of those genes will be
intermediate in
pattern and is known as Tonkinese. A quirk of the Siamese form of
albinism is that it is temperature
dependent with
warm areas of the
body being paler than cooler areas. For this
reason , it is often
described as "colour restriction" rather than albinism.
Pink-eyed albino appears to be recessive to all of the other albino
mutations.
The
albino cat reported in Europe and the USA seems to be intermediate
between pink-eyed albino and blue-eyed albino. Although it has the
white coat of a true albino, its eyes have ruby red pupils and pale
blue irises. A true pink-eyed albino was reported in
1931 and again
in 1980s in the USA. Albino kittens have turned up more recently in
the
Bengal breed, unsurprising since albinism is found in the Asian
Leopard Cat (the wild parent of the Bengal).
Dominant
white is the colour associated with deafness in cats. Dominant white
masks all other colours and cats may have blue, orange or odd eyes.
Those with blue eyes have a high chance of deafness. Those with one
blue eye have a high chance of deafness on the blue-eyed side. Those
with orange eyes are far less likely to be
deaf . Some dominant white
kittens are born with smudges of coloured fur on top of the head,
this smudge of colour
usually disappears by adulthood, but kittens
with colour smudges are more likely to have normal hearing.
The
gene for white spotting can also create the
impression of a self
white cat. This gene is semi-dominant and is variable in the way it
is expressed - a cat may have no
visible white spots or may be wholly
white and all stages in between those two extremes. Unlike dominant
white, white spotting is not linked to deafness.
COLOUR
RESTRICTION, TICKING AND TIPPINGAnother
form of modification is colour restriction. This is seen in
colourpointed cats where the colour is restricted to the head, tail
and legs (
plus scrotum in
males ). This is a form of partial albinism.
As well as restricting where the colour will be exhibited, it tends
to "bleach out" the colour to a
greater or lesser
degree depending on the type of colour restriction. It may seem odd to think
of these as solid colour cats, but genetically they are; they have
just had a "special effect" overlaid on them.
There
are three colour-restriction
patterns :
In
the Siamese (Himalayan) pattern, there is maximum contrast between
the
points and the body colour.
In the Burmese, there is the least
contrast but just enough to be
able to see that the cat is not a
single solid colour.
In the "Mink" Tonkinese, the effect
is moderate.
The
self colours may have different names in these cats. Alternatively a
colour which appears identical to one of the solid colours may be
genetically different because of the
mild to moderate bleaching
effect. A seal-point Siamese may appear to be brown, but genetically
it is black!
In
Abyssinian and Somali cats, the agouti gene causes the colour to be
distributed in bands along each hair. This creates a ticked effect.
The most confusing aspect is "red". The bright red colour
in sorrel Abyssinians is
really cinnamon. The dark red of the Usual
Abyssinian is genetically black. Where registries recognise the
sex-linked red and sex-linked cream colours the colour name is
prefixed by the words "sex-linked". In the USA, the
sex-linked colours are apparently not recognised to avoid confusion
with the sorrel and fawn colours. To the
naked eye (or without the
benefit of a pedigree chart), the colours are practically
indistinguishable.
It
has been thought there were 2 different shades of sorrel red: a
bright coppery red and a dark red characterised by an influential
American Abyssinian sire called
Champion Dhmahl's Diablo. Some pale
kittens darken to red, while others become deep solid-
looking red
with minimum ticking. The dark red is more likely to be chocolate.
Chocolate and lilac, along with the silver series, are
considered alien to many
North American breeders, but are familiar in Europe.
Full Expression Sepia (Burmese) Mink (Tonkinese) Pointed (Siamese) Abyssinian/Somali Australian Mist Black/Brown (in tabbies)/Ebony
Brown/Sable/Seal Sepia
Sable/Natural Mink
Sable/Seal
Usual/Tawny/Ruddy/Brown
Brown
Blue
Blue/Blue Sepia
Blue
Blue
Blue
Blue
Chocolate/ Chestnut/Brown
Chocolate/ Champagne Sepia
Chocolate/ Champagne Mink
Chocolate
Chocolate
Chocolate
Lilac/Lavender/
Frost Lilac/Platinum Sepia
Lilac/Platinum Mink
Lilac/Platinum
Lavender
Lilac
Cinnamon
Cinnamon/Cinnamon Sepia
Cinnamon/
Honey Mink
Cinnamon
Red/Sorrel
Gold Fawn/Light Lilac
Fawn/Fawn Sepia
Fawn
Fawn
Fawn/Beige/Dilute Sorrel (non sex-linked)
Peach
Red
Red/Red Sepia
Red
Red
Sex-linked red
Red
Cream
Cream/Cream Sepia
Cream
Cream
Sex-linked cream
Cream
The
colour can also be restricted to the ends of each hair. This is
caused by a gene for silver. Chinchilla (
shell ) is the lightest form
of tipping or shading - hair tip is coloured and hair shaft is
silver, giving a sparkling appearance. Shaded is the next degree -
the colour extends further along the hair shaft, darkest on the back
(where fur is longer) to create a mantle of shading. Smoke is the
heaviest tipping - the undercoat colour is reduced to a small
band near the hair
root so that the cat appears to be solid colour with a
pale ruff until the coat is parted and you can see the silver roots.
In goldens, the effect is similar except that the hair shaft is gold
rather than white. These cats are still self colours, but the colour
distribution has been modified!
There
is another effect known as silver-tipping; this is the sparkling
silver tips to the otherwise black fur of Chausies. It is an effect
inherited from
Jungle Cats (F chaus) and is seen in purebred
melanistic Jungle Cats. Affected cats are self coloured, but with a
modifier which is new to domestic cat genetics.
A
WIDER PALETTE OF COLOURSThe
previous sections dealt with solid colours and how they are affected
by two
types of dilution, three types of colour restriction, agouti
ticking and silver/golden shading.
There
are genes which control how evenly the hair is coloured i.e. the
bands of colour on each hair. In agouti cats, it is
easy to see
different bands of colour using a magnifying
glass . In cats with
apparently solid-coloured fur, you would need a microscope. Even
though the effect on an
individual hair can't be detected, the
overall effect on an area of fur is make the colour more or less
dense i.e. darker or lighter.
In
general the self colours (with
plain English descriptions) are:
Colour name Plain English Description Albino
White
Amber
Born black, brightens to bright apricot to cinnamon with age.
Apricot
Pink-brown or hot cream, with a metallic sheen,
Beige
Abyssinian/Somali: Non sex-linked cream, Fawn
Black
Jet-black
Blue
Blue-grey
Brown
Chocolate. Genetically black cats with tabby pattern are known as brown tabbies. (Burmese "Brown" is equivalent to black.)
Caramel
Caramelised blue, cafe-au-lait colour (biscuit colour), cool toned bluish fawn, metallic sheen
Champagne
Burmese/Tonkinese: equivalent to chocolate
Chestnut
Oriental:
Medium -dark brown, equivalent to chocolate
Chocolate
Medium-dark brown
Cinnamon
Milk-chocolate (reddish) colour
Cream
Buff, dilute of sex-linked red
Ebony
Foreign : equivalent to black
Fawn
Abyssinian/Somali : hot cream (non sex-linked cream), equivalent to Light Lilac
Light Amber
Born blue, brightens to pink-beige or fawn with age.
Frost
Lilac/lavender
Gold
Australian Mist: equivalent to cinnamon
Honey
Burmese/Tonkinese : Equivalent to chocolate/chestnut
Indigo Lavender
Pinkish grey (dove grey)
Lilac
Lavender
Light Brown
Equivalent to cinnamon
Light chocolate
Burmilla: Milk chocolate
Light Lilac
Equivalent to fawn
Natural
Tonkinese: equivalent to sable/seal
Peach
Australian Mist: Pink-brown, equivalent to light lilac/fawn. Peach is also seen as a dilute of
Russian Blues and may be caramel.
Platinum
Burmese/Tonkinese: Equivalent to lilac/lavender
Red
Rich ginger red (poor reds are yellowish due to other genes)
Red
Abyssinian/Somali: Equivalent to cinnamon
Ruddy
Abyssinian/Somali: Equivalent to black/brown
Sable
Burmese: Dark brown (genetically black)
Seal
Siamese: Dark brown (genetically black)
Sorrel
Abyssinian/Somali: Equivalent to cinnamon, honey mink of Tonkinese
Taupe
Caramel dilution of lilac/lavender
Tawny
Abyssinian/Somali: Equivalent to black
Usual
Abyssinian/Somali: Equivalent to black
White
Non-albino white, this is the absence of colour.
In
all likelihood, there are many other genes which subtly alter the
colour e.g. by modifying the hair structure
slightly to change the
way it absorbs or reflects light or by affecting the distribution of
the pigment granules in the hair shaft. The appearance of
silver-tipped black cats suggests that hybridisation is
going to
introduce new colours and effects into domestic cats.
Some
colours which have already
appeared are still disputed. For example
"caramel" is a subtle form of dilution. It does not affect
non-dilute colours (black, chocolate, cinnamon), but it changes the
appearance of already dilute colours (blue, lilac, fawn). Caramels
which are genetically blue cats have a brownish cast while those
which are genetically lilac are lighter in
tone . So should they have
separate colour names e.g. blue-caramel (caramel), lilac-caramel
(taupe) and fawn-caramel or should all the slightly varying colours
be lumped under the name "caramel". They jury is still out
on this one, but it demonstrates the importance of knowing what
colours the cat has in its pedigree!
Another
new colour, indigo, is described as a richer, darker version of blue.
This suggests some sort of intensifying effect acting on diluted
colours. However since blues can be variable in hue, there is no
confirmation that indigo is due to a specific gene or that it is
genetically heritable. The only example I have seen depicted a
tortoiseshell cat with blue-black and hot cream patches i.e. to
richly coloured to be blue-cream tortoiseshell, but not a red-black
tortoiseshell. This could
mean a gene with the opposite effect to
caramel i.e. it acts on dilute colours only, but it intensifies them.
If so, it is probably invisible to the naked eye and only noticed in
individuals with the most extreme effects of that gene. The same gene
would have no discernible effect on non-dilute colours since there
are already at their most
intense .
Note:
since other breeders describe indigo as a darker version of blue, the
"blue-black" may have been exaggerated by lighting.If there
is a colour intensifier
turning blue into indigo, it could be
expected to work on the other dilute colours as well e.g. turning
lavender into deep lavender, fawn into rich fawn and cream into rich
cream. The differences would probably be too slight to be visible -
it is already
hard enough to detect the caramels!
According
to Inina Sadovnikova, "I believe every breeder has had cats of
one and the same colour, but of a different
shade . Take a black
(brown) tabby, for instance. They range in shades from a light grey
with a black pattern to a rich brown with a black pattern. Reds are
also very different, from a ginger to an
intensive orange. The same
concerns blue, I have seen blues so dark that one doubts if they are
really blue and not black. From my
experience , I
tend to think that
there is a modifier, though I don't
know of any studies of this
factor. The litters of my female Konkordia always had at least one
kitten coloured intensively, either a very dark black tabby or a very
dark red tabby. She has a light shade of colour, but her grandmother
is darker and also had several dark kittens in her litters. This
looks like a recessive, but one needs a lot more of statistics to
prove if and how it is inherited. A dark shade is desirable for red,
but at present undesirable for blue. So I don't know if "indigo"
has any future."
ODDITIESStrange
as it may seem, in some
animals the mother's
diet can affect coat
colour.
Recent work at Duke
University in Durham, North Carolina, has
shown that in a certain
strain of
mice , the "agouti" coat
colour gene can be turned off through methylation. The extent of
methylation was dependent on the mother's vitamin intake during
pregnancy. (Methylation turns off genes by chemically modifying
them). The effect has not been observed in cats, but in theory it
could turn genetically agouti (ticked) cats into solid colours.
Some
cat shelter workers have noticed apparently self red kittens turning
into black adults. Solid black is known to be
prone to rustiness
through damp or sunlight and evidently, in some
cases , to
conditions in the womb. Self black kittens are often "rusty" at birth,
though few cases are as striking as that of a ginger kitten called
"Marmalade" who was entirely black at 6 months old
(personal correspondence).
A
better documented oddity is that of apparently self red or self black
female cats that are genetically tortoiseshell cats. In rare cases,
one colour predominates to such an extent that the other is
represented by a few isolated hairs.
BEAUTIFUL
BICOLOURS - TUXEDO AND MAGPIE CATS
Copyright
2002 - 2016 , Sarah HartwellBicolour
cats go by various names and
come in many patterns. They range from
almost solid colour cats with a white
throat locket or white
tail-tip, through to almost solid white cats with black smudges on
the nose or between the
ears . You may have heard of them as tuxedo
cats (white mitts, white
belly and white
chin with an optional white
tail-tip) or patched, pied, particoloured, harlequin or magpie cats
(usually white with coloured splashes on the back and top of the
head). The term covering all bicolour cats is "piebald" or
"white spotted" with some variants of the pattern being
called the Seychelles pattern.
DIFFERENT
TYPES OF PIEBALD The
diagram above shows a typical progression from solid colour through
to solid white. The number by each diagram is the "
Grade "
of spotting from Grade 0 (no spotting) through to Grade 10 (white
spotting has obscured all of the base colour). The "solid
colour" can be one of the true solid colours e.g. black or grey,
or a tabby colour or tortoiseshell (the bicolour is then known as a
calico and is actually a tricolour). Non-pedigree cats have a diverse
range of combinations not recognised in the pedigree world - the
"solid" area can be Abyssinian ticked (Aby-and-white),
smoke, shaded or tipped. Black-smoke-and white is an attractive
combination if not actually encouraged!
The
Van pattern seen in pedigree Turkish Van cats and in the Seychellois
(a Van-patterned Oriental) is Grade 8 - Grade 9 Piebald and
represents the most extreme of the 'Seychelles' patterns. In the
Turkish Van, the colour is restricted to auburn (red) or cream
patches on the head at the base of each ear; the tail is the same
colour as patches, often with darker
rings because red and cream are
not true solid colours. Although auburn has long been the
traditional colour of Turkish Van markings, other colours are being developed
within different cat fancies, but in its
native Turkey , the Turkish
Van actually refers to an all-white cat (Van Kedi).
(Almost) Van Pattern (Grade 8/9 Piebald)
Grade 7 Piebald Littermates
Grade 7 Piebald
The
Van pattern is also found in Persian Longhairs in the form of Van
Bi-Colours & Harlequins. These often have additional markings on
legs, and one or two small splashes of colour on the body. The
Seychellois is an Oriental type cat, occurring in both longhair and
shorthair forms, exhibiting varying degrees of the Van pattern:-
Seychellois
Neuvieme is a white cat with coloured tail and head
splashes
Seychellois Huitieme is white with coloured tail
and head splashes plus additional splashes of colour on the
legs
Seychellois Septieme has splashes of colour on the legs and
body in addition to those on the head and the coloured tail.
British
cat fancier Pat Turner defined the different levels of white spotting
as: Grade 2 - "White
Trim "; Grade 3 - "Mitted";
Grade 4 - "
Irish "; Grade 5 - "Saddle"; Grade 6 -
"Pied"; Grade 7 - "
Chinese "; Grade 8 -
"Harlequin"; Grade 9 - "Van". In
exhibition -quality bicolour cats, symmetrical markings were
preferred .
The
placement of the colour patches is variable and related to how the
embryo develops and expresses the genes it has inherited. As a
result, even more extreme colour restrictions can turn up, for
example Wanda below (
photos provided by Peggy Alden-Clapper) is an
eyecatching
variation on Grade 9 Piebald - all white apart from a
black tail, but no splashes of colour on the head or body.
Variation Grade 9 (Extreme Grade 9)
"Moorish-headed" Cat (Variation on Grade 9)
In
1896, Jean Bungartz wrote in his "Illustrated Book of Cats"
(in
German only): The black-headed or Mohrenkopf (Moorish-headed) cat
must be
clean white, with contrasting colour on the head and tail.
Consistent specimens of this variety are extremely rare and it can
probably be regarded as one of the most peculiar colour patterns of
the domestic cat. The colour of the head and tail can be either
black, grey, blue or
yellow with no white hairs except those
regularly showing up on the head. As previously mentioned, cats with
good and correct markings are
highly valued.
THE
TYPICAL RANGE OF BICOLOUR PATTERNSPiebald
cats are extremely common and varied in appearance. The white
spotting can occur with any colour/pattern and varies from minimal
white through to almost all white. The smallest amount of white may
be no more than a white locket and a small white belly patch, each no
more than a few white hairs. Though this pattern doesn't have a
descriptive namem the term "locket cat" has been suggested.
The
image at the top of this page and the description below is a
typical progression through the different grades of piebald. Due to
developmental effects at the embryo stage, there are further
variations on this general
theme !
Tuxedo Pattern
White
facial markings
At
one end of the
scale is the white locket, followed by the familiar
tuxedo pattern where the belly is largely white. As the degree of
white spotting
increases , the white spreads up the neck and onto the
chin (as shown in the three-
quarter Persian above). The cheeks may be
white or have white spots and there may be a white blaze (an
inverted V) from the muzzle up between the eyes or a white "teardrop"
on the nose (as shown in the cat above right). If the neck and chin
are white, the
front paws are also usually white.
Mask-and-mantle pattern
Saddle pattern
Grade 7 Piebald (with white
ringed tail)
As
the degree of white spotting increases further, the white extends up
the
sides of the cat, up the forelegs (stockings) and onto the hind
paws. The next step is all white hind legs, white fully around the
neck and the white blaze may
extend right between the ears. Some cats
also have white ear tips. This pattern is sometimes known as
"mantled" because the cat appears to be wearing a coloured
cape with a hood or mask. The mask-and-mantle is a common bicolour
pattern as shown above.
As
the amount of white increases further, it simply shrinks the mantle
into a saddle. The mask may also shrink back to a "cap"
giving the cap-and-saddle pattern (as with the cat in the above
centre photo). Further white spotting breaks the saddle up into
smaller patches as shown in the black-and-white Grade 7 piebald cat.
Sometimes one or more white rings encircle the tail - for some reason
this ringed effect seems more common in tabbies.
With
any degree of spotting, there may be coloured smudges on the cheeks,
chin or nose. Some cats also have black
toes on otherwise white paws.
Jean
Bungartz described two bicolour patterns in his 1896 book "Die
Hauskatze, ihre Rassen und Varietäten" (Housecats, Their
Races and
Varieties ) in " Illustriertes Katzenbuch" (An
Illustrated Book of Cats). His description of the "masked cat"
is the tuxedo pattern, which he describes as "sometimes the
tail-tip is white also. The eyes of this variety are bright yellow
with black rims.
Regular and sharply defined white patches create the
most beautiful Mask Cats which have many admirers."
Bungartz
describes a less familiar bicolour he calls the black-headed or
Moor -headed cat (Mohrenkopf) which was clean white, except for the
head and tail, which were black, grey, blue or yellow with no white
interspersed "except those showing up regularly on the head".
Consistent specimens of this variety were extremely rare and
valuable . His illustration depicts a cat with wholly black head, but
it is possible he was describing the Van pattern.
It
is possible to combine piebald with bicolour. Bicolour Siamese have
been bred in Europe to a mixed reception. A few Himalayan breeders
breed bicolour Himalayans, using bicolour Persians to introduce the
white spotting pattern. Paul Beall, Richmond,
Texas is one such
breeder.
Paula 's photo (below) shows a bicolour (piebald) Himalayan,
but
unfortunately this cat has not produced piebald-point kittens and
Paula has decided not to reintroduce the gene from Persians.
GENETICS
OF PIEBALD CATSWhen
the amount of white is small (under 40%), it is called low-grade
spotting and comprises the white belly patch, mitts, locket and
blaze. In medium grade spotting, the amount of white varies from 40%
to 60% of the coat and is the typical pattern of a show quality
bicolour (a mask and mantle effect). When it is extensive (more than
60%), it is called high-grade spotting - the Seychellois or Van
pattern.
Piebald
spotting is a semi-dominant gene with very variable expression. Low
grade spotted cats and some medium grade, spotted cats are
heterozygotes i.e. they have only one copy of the white spotting
gene. Other medium grade spotted cats and all high grade spotted cats
are homozygotes i.e. they have 2 copies of the gene. Where cats are
in the medium spotted range it is generally impossible to know
whether they are heterozygotes or homozygotes unless they are bred to
a cat known to be either homozygous or heterozygous. To further
complicate matters for breeders, some apparently non-piebald cats are
really piebald cats whose white bits are so minimal they might be no
more than a few hairs in the groin or at the tip of the tail!
In
January 2016 , it was announced that piebald patches form when cells
fail to
develop in the womb. The gene for white spotting affects the
embryo cells (melanoblasts) which will become pigment-producing skin
cells (melanocytes) which make the pigment for hair. Pigment cells
move and multiply as an embryo
grows and there aren't enough cells to
cover all the skin, so the
animal gets a white belly. The findings
were published in the journal Nature Communications. The pigment
cells 'fail to follow instructions' during early
development . They
move and multiply randomly as an embryo grows, without complex
cell-to-cell
communication sending them in one direction as
once thought. The University of
Edinburgh 's Dr
Richard Mort said that the
cells move and multiply at
random which is not what was expected. The
University of Bath's Dr Christian Yates said: that piebald patterns
could be caused by a faulty version of a gene called kit. What the
researchers found was
counter -intuitive. Previously it was widely
thought that the defective kit gene slowed cells down, but instead
they found that it reduced the
rate at which the pigment cells
multiply. This did not
surprise cat fanciers who had noticed that
pigmented patches could fit together like a jigsaw and likened the
process to “plate tectonics” where pigmented patches
drift across the embryo’s skin leaving unpigmented areas inbetween the patches.
Researchers at the Universities of Bath and Edinburgh said that in
addition to kit, there are many other genes that can create piebald
patterns, but their the mathematical model can explain piebald
patterns regardless of the genes involved.
This
wasn't entirely surprising to many cat fanciers with an
interest in
genetics or embryology! Independently of
scientific researchers, and
based on observation, fanciers had some ideas of their own, which
have turned out to be
close to the mark.
Many
cats have patches which look as though they could be fitted together
like jigsaw pieces; for example a coloured
spot on a leg might
correspond to an inlet on a coloured patch on the flank, exactly as
though a
piece of coloured area has
broken off and migrated
elsewhere. Spots could end up almost anywhere depending on the timing
of cracking, the
size of the coloured domains, and the trajectories
they take over the embryonic surface as it grows. Terada and Watanabe
found it possible to fit all the coloured areas of cat coat together.
The seams can then be projected onto the surface of a sphere (the
embryo). As the sphere expands, the coloured area cracks apart. Think
of a
balloon covered in solidified chocolate: the balloon can expand,
but the chocolate can't. The cracked solid surfaces then gave
patterns just like those found on bicolour cats. The swirled patterns
in
particular fit this hypothesis.
Part
of this theory was that the patterning of black and white was the
result of the skin surface "cracking" during early embryo
development. The skin of such bicolour cats at an early embryo stage
would be basically pigmented, but the dominant S (white spotting)
gene, causes the pigmented surface to
crack into domains or
islands .
These islands drift apart over the embryonic surface as the embryo
grows, but the pigment cells don't multiply fast enough to fill the
spaces between the
island . That leaves white areas in the
regions between the islands of pigment. It may help to think of it as similar
to the
movement of the earth's continents with areas of sea
inbetween. It is just as though the white areas were scar tissue
produced by the cracking. There are not enough melanocytes
available to fill the white areas as their surface expands. This means that the
black domains can end up pushed together to form a single tuxedo
style black area (albeit there may be some small white markings in
this single black area). The white belly area might be a ventral
(belly) seam from a ventral crack earlier on - it is suspected that
the belly area expands
greatly during embryo
growth . Megacolon in
cats and exposed gut conditions in some rabbits upholds this theory.
Black
feet could indicate a black domain that has been pushed to the
foot extremity by the expansion of the ventral region at the same
time that the
limbs are being
formed .
Where
the white spotting occurs over the eyes, it may affect the eye
colour. Thus a few bicolour cats have blue eyes. Another
interesting effect of white spotting is in tortoiseshell cats. Tortie cats with
little or no white tend to have brindled coats with intermingled
black and orange hairs. However, the more white there is, the more
the black and white will also be separated out into patches instead
of being intermingled. This is also explained by the mechanism
detailed in the 2016 report findings. The black pigmented cells that
have moved across the embryo surface multiply to form black islands
(clonal patches), while the red pigmented cells that moved across the
surface multiply to form red patches.
OLDER
/ ALTERNATIVE THEORIES FOR BICOLOUR PATTERNSAbove:
"Olga", an attractive brown bicolour
owned by Sarah Richie
It
used to be thought that when the melanoblasts
arose from the "neural
crest" - the area along the back of the embryo -they migrate all
over the body during
formation of the skin. Where cells failed to
reach their allotted positions
before the skin was fully formed,
those areas lacked pigment. This
seemed to explain why the white is
most often found on the paws, belly and
chest - those areas are the
most remote from the neural crest and take
longest to reach. The
slower the
migration of cells, the less colour there will be. It also
explained why the back and the tail may be coloured in an otherwise
all white cat - those areas are closest to the neural crest and the
pigment cells didn't have to migrate very far.
Another
theory involved either of two cellular mechanisms in white spotting
that "turned off" pigment. One mechanism was apoptosis
(programmed cell
death ) reducing the melanoblast (pigment granule)
population. In other words, the colour cells migrate over the whole
surface of the embryo, but then selectively die out. The other
cellular mechanism involved intracellular chemical communication
whereby colour cells are biochemically turned off in certain areas.
Both of these suggest a chemical
gradient so that cells at the
extremities tend to be first affected and stop producing colour.
Another
hypothesis for the distribution of white was originally presented in
papers published by T Terada and T Watanabe in a
1930s Japanese journal. This hypothesis is now being investigated using computer
simulation. There are several "unknowns" with the
current hypotheses: the relative frequencies of the 10 grades of white
spotting
given that white spotted cats may be either SS or Ss; the
relationship, if any, between birth order and patterning; and whether
the "swirled" pattern is related to any birth defects or
any difficulties during pregnancy. The melanocyte migration
hypothesis may not
contain the whole story, especially where swirled
patterns, black feet on white socks and
skunk stripes are concerned.
Some
cat breeders believed there were flaws in the conventional melanocyte
migration theory. For example a breeder
working with American
Shorthairs has been crossing Van pattern American Shorthairs to
bicolour and spotted Van pattern cats since the mid 1990s. She found
that the melanocyte migration theory could not
account for some of
the spotted patterns these breedings produced. Alternative theories
from other white spotting genes and mechanisms in other
species (
dogs ,
horse , pigs and goats) also could not account for what was
appearing in her cats,
particularly with 60%, 70%, 80% and 90% white
on a cat. The terminology used differs from the Grades 1 - 9 of the
cat fancy; 90% white with a
lot of
random spots is referred to as Level 15. Selective breeding has
isolated most of the white on the cats to a single
layer of white.
She can now produce solid coloured cats from the mating of two
bi-colours/pied/vanish cats. In addition, all of her
best breeding
cats have black feet. Breeding experiments involved mating a level 15
stud to a solid black, two Level 7 piebalds, and a Level 9 cat. A cat
with a large degree of white is most probably homozygous for the
white spotting gene and mating it to other white-marked cats which
also
carry at least one white spotting gene should not, in theory,
produce solid-coloured cats. An alternative hypothesis is that the
cats have the dominant white gene (the one related to deafness) and
that a second gene is causing this to break down so that spotting
appears. It is possible to produce coloured cats from mating two
all-white cats since each parent needs only one copy of the dominant
white gene to make them all white and can carry masked genes for
other colours.
OTHER
PIEBALD CATSThere
are quite possibly several genes which
influence white spotting. For
example, the patterns above might not be due to a single gene - there
may be several other genes which modify its effects. There are also
other piebald patterns which appear to be due to different genes or
to cats being homozygous for a modifier gene since the effect is
relatively
uniform and predictable.
The
gloves (mitts) on Birman and Snowshoe cats appear to be due to an
incompletely dominant gene. The gloves may
vary in
length but they
are restricted to feet and/or legs. The white markings on the
forehead and chest of breeds such as the Snowshoe may also be due to
a gene which
limits the amount of white. Lockets - those small spots
on the throat, chest, stomach and groin of otherwise solid coloured
cats also seem to be due to a different gene - one which is normally
hidden by the more extensive white spotting of piebald cats. There is
also the
phenomenon of white toes occurring on otherwise coloured
cats.
In
the
York Chocolate breed, there is a particular white displacement in
bicoloured individuals. The placement of white maintains the same
configuration in all successive generations. This has been termed
"Spotting Particolour" and may be due to an allele
(variant) of the White Spotting gene. According to this theory, the
White Spotting gene appears to have 4 variants: non-spotted, spotted,
particolor, and Birman mitted. Spotted is the dominant form and is
variable expressed. Non-spotted is the recessive wild-type and
produces a coat without white. The hypothetical Birman allele (or
Birman mitted) is also variable, but confines the white spotting to
the legs and feet. The hypothetical Particolour allele produces an
inverted white "V" with the apex in the centre of the
forehead and passing through the centres of the eyes plus a white
chin, chest, belly, legs and feet are white. Particolour is also
variable and its least expression may be a white locket or white spot
on the forehead. The existence of breeds such as the York Chocolate
(consistent particolour pattern) and Birman and Snowshoe (consistent
mitted pattern) appear to support the existence of a white
particolour gene and a white mitted gene.
A
pattern which has only rarely been reported in cats is the
belt ,
blanket or sheet marking. This is common in pigs and
cattle and in
Dutch rabbits where a band of white encircles the animal's body like
a belt.
Another
cause of white spotting is a somatic mutation i.e. some skin cells
have a chance mutation which prevents them from producing pigment.
This is not hereditary.
Leukoderma
("white skin"), leukotrichia ("white hair") or
vitiligo, is a
cosmetic condition that produces a "cobweb"
or "snowflake" effect and is most easily seen on black
cats. White spots appear on the coat; these become more extensive
with age until the cat has a white lace pattern on the black fur.
Ultimately the cat may go completely white or be left with
diminishing isolated patches of colour. This condition has been seen
in black leopards ("cobweb panthers"),
humans , dogs and
other animals. This must not be confused with the normal sprinkling
of isolated white hairs which appear in a cat's fur during its
lifetime . "Leukotrichia" is a generic term. Acommon term is
"piebaldism" because it causes white patches in the skin
and fur. It is an "aquired depigmentation" that occurs
during the cat's lifetime, is usually progressive and may be
triggered by
illness or environmental factors. Ultimately, a cat with
leukoderma may become almost entirely white. Antibodies are formed
against the pigment-producing melanocytes. The melanocytes are
destroyed
leading to the white areas. A type of leukoderma has been
identified in some Persian cats and these are used as laboratory
subjects in the
study of depigmentation conditions. Periocular
leukotrichia, causes the fur around the cat's eyes to become pale -
as though the cat is wearing spectacles.
Vitiligo in a big cat - the "cobweb panthers" that turned progressively white.Charva with feline vitiligo (Jason Reeves). "Charva"
(Jason Reeves) has vitiligo; she was a black cat with patches of
slightly longer/softer black hair. In 2009 she turned 4 and developed
a patch of white hair. Since then the patches of white have turned
into stripes, spots, and patches. Her skin is turning pink as well
due to the loss of pigmentation.
In
2011, Kimberly Sexton of New York City
sent these photos of her cat
Frankie . Kimberly's 14 year old cat
Miko (white with grey markings on
his head and tail) had recently died and in his last 3 years had
formed a close bond with her younger cat, Frankie, a mackerel tabby.
The two cats often slept intertwined. Two years before Miko passed
away , Frankie developed a white spot of fur under his neck, while his
chin and nose became paler. As time passed, Frankie's white areas
spread and new
ones developed around his neck and
behind his
shoulder blades. Kimberly joked to friends that Miko's white colour was
rubbing off on Frankie as they slept! Frankie's white areas are
likely to continue spreading, but the effect appears entirely
cosmetic.
On
coloured cats, hair regrowth around scars is often white. Lizzie
Ellis (The Feline Rescue
Association Inc, Maryland, USA) provided
these photos of a grey male cat with white patches due to scarring.
Where the skin was injured or burned, the fur has grown back white,
not grey. The cat had suffered frostbite injuries. Some dark coloured
cats show white hairs in their coat as they grow older - some
follicles stop producing pigment, just as humans get "grey"
hairs. Unlike the cobweb effect (where pigment loss occurs in
patches, like snowflakes or strands of gossamer), age-related white
hairs are evenly sprinkled across the body giving a salt-and-pepper
effect; there may also be greying around the muzzle. It is a normal
part of ageing although cats seem far less prone to
getting grey
hairs than do dogs. It should not be confused with the white patches
found in vitiligo.
SWIRLED
PATTERNS AND SKUNK STRIPESWhile
the piebald pattern is generally fairly symmetrical until the white
exceeds 60% of the body surface, some cats
exhibit a variety of
swirled patterns. This may simply be due to the way the embryo
developed or it may be the interaction between different genes which
affect white spotting. The two cats below are unrelated, but both
have swirled black and markings and black markings on the face. Both
also have black toes. Coloured toes sometimes occur on bicolours -
these can be individual toes or multiple toes. It may even look as
though a white-footed cat has paddled through coloured paint, in
which case the colour usually extends up the back of the leg.
Coloured toes may possibly be another gene (modifier) interacting
with the white spotting gene.
Note:
The cat shown top left has a mild form of radial hypoplasia which has
caused her deformed forelegs; she also has a slightly deformed skull . Swirled Patterns
More
unusual is the "skunk marking" - a white dorsal stripe.
Because pigment producing cells migrate away from the neural crest,
the dorsal area itself usually remains coloured in low to medium
grade spotting. The appearance of a white dorsal stripe is unusual
and appears to be hereditary.
Photos courtesy of
Magnificent MunchkinsBRINDLED
BICOLOURS AND "TWEED" MUTATIONPandora (owned by
Bill B, Granby, MA, USA) is a brindled cat with what
appears to be an unusual mutation. She has the brindled pattern
normally seen on tortoiseshell cats, but the patches which should be
red are white! The brindling and facial pattern is typical of
tortoiseshell cats, but it seems that 15 year old Pandora has a
mutation that prevents her producing red pigment. An alternative
explanation is that Pandora is chimera formed when a black embryo and
a white embryo fused in the womb; however chimeras tend to have a
patched appearance rather than being thoroughly brindled, this
makes chimerism a less likely explanation. A third possibility is that
Pandora has additional X chromosomes (XXX or XXXX instead of the
normal XX female), however this genetic anomaly is associated with
mental retardation and
physical anomalies/deformities (this is not
Klinefelter
syndrome , Klinefelter syndrome is
only found
in males e.g. XXY or XXXY). These two conditions can be identified
using tissue samples, but this isn't recommended in an older cat as
it involves sedation or anaesthesia. It seems likely that the gene
that should produce red pigment is faulty or that some other gene is
masking the red pigment out. Since Pandora was spayed before Bill
obtained her, it isn't possible to breed her to see if it can be
inherited. I have seen the opposite mutation - where a tortoiseshell
cat produced red pigment, but not black, resulting in a red, cream
and white brindled cat - but this is the first time I have seen a
black-and-white brindle where the red is absent.
More
brindled bicolours are explained in the separate page on
Roan,
Tweed and "Salt and Pepper" ColoursTHE
CHINESE HARLEQUINDuring
the 1980s, there were
attempts to breed shorthaired cats with a black
tail, black patches on the head and small black (or other solid
colour) patches or spots on the body. Named Chinese Harlequin, it was
to resemble cats found in
ancient Chinese art. Although still listed
by some registries, it appears to now be
extinct due to the
difficulty of breeding bicolours with consistent spotted markings. A
similar "strikingly spotted" cat, the Gao Taem, is seen in
ancient
Thai art and is described as having, black marked forepaws,
black and white ears, black shoulders, two black spots on the back
and black shoulders. In
total there should be nine horse-like black
spots on an all white background. If it existed as a breed, the
mutation creating these
features has been lost. In all
probability it
was a form of Seychelles pattern. Some bicolours have black toes or
paws and and some breeders have attempted to fix this trait to create
a black-footed Van-type bicolour.
Also
depicted in Thai art (1676) is the Vichiens Mas which is shown as
white with dark ears, nose, paws and whiskers. Although depicted as
black and white, it seems to be a stylised or idealised depiction of
the seal-point Siamese.
"BELTED"
OR "SHEETED" PATTERN"Belted"
means a solid coloured animal with a belt of white around its
middle ,
such as is seen in Dutch Rabbits. This pattern has
occasionally been
seen in
Spanish feral cats. "Sheeted" means a wider the
band of white i.e. from shoulders to haunches.
THE
"DALMATIAN" OR "APPALOOSA" CATThe
concept of a white cat with coloured spots, akin to a Dalmatian dog
or Appaloosa horse, has intrigued numerous people. In some feral
colonies, white cats with numerous small black splashes have been
found alongside bicolour cats with the conventional Grades 1 - 9 of
white spotting. This suggests the presence of modifier genes which
affect the distribution of colour and white. Inbreeding causes genes
to double up so that recessive genes and traits controlled by
multiple genes become visible. It would be possible to have genes
which interact with the semi-dominant white spotting gene such that
small patches of colour break through the white or which cause a
breakdown in white spotting.
Some
breeders report a
consistently high
incidence of numerous small splashes of colour on the body in certain
breeding lines which suggests to them that some other gene(s) is
being inherited alongside the white spotting gene. This may see a
repetition of the Chinese Harlequin programme.
"BIMETALLIC"
SIBERIANS & PLATINUM PERSIANS
2013-2014,
Sarah Hartwell
Many
thanks to Silvia Perego and Lesley Morgan for allowing the use of
their photographs on this page.Note
on Terminology: At present, terminology isn't standardised.
"Bi-metallic" describes a visual effect, while "sunshine"
is the (current) proposed genetic name. In Siberian Cats,
sunshine-silver produces the bi-metallic pattern.For
some years, strangely patterned Siberian cats have been turning up.
Some are covered in A Torbie Dynasty:
A
Torbie Dynasty.
Caroline Sharp in
Germany had several generations of apparently
tortoiseshell-tabby male cats. This should be impossible as tortie
tomcats are genetically abnormal in some way and even when
fertile they should not produce further generations of tortie tomcats. They
couldn’t all be chimeras, so there had to be some unidentified
mechanism at work.
Other
Siberian cats had both silver and golden areas of fur and were dubbed
“bimetallic.” This X-colour (mystery colour) looked similar to
the partway stages of the amber colour change seen in Norwegian
Forest Cats. Siberian breeders had referred to their cats as "golden"
but this term clashed with the wide band colour found in Persians,
Exotics and British Shorthairs. The official term "sunshine"
has been proposed to distinguish Siberian golden from "wide band
golden".
At
birth, Siberian "Sunshine" resembles the early stages of
the amber (ee) colour change in Norwegian Forest Cats caused by a
non-extension gene. However, the Siberian cats tested negative for
the amber gene. There were no genetic tests for Wide-band or for
silver inhibitor, let alone for Siberian sunshine, but it can be
distinguished visually and by studying pedigrees. Bimetallic
colouration has also been seen in the Kurilian Bobtail and in
random-bred cats in the
Ukraine .
Judge Lesley Morgan come across a number of strangely coloured cats that
had been nicknamed “bimetallic” as they displayed a mix of silver
tabby and golden tabby in their coats. The effect was
beyond
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