SILVER AND GOLD ; SMOKE, SHEDED AND TIPPED CATS
Copiright 2003-2010 , S Hartwell
There are a whole host of terms used to describe the different smoke, shaded and tipped cats. Different terms are used depending on whether a cat is longhaired or shorthaired. A number of terms are historical, but can still be found in print. Where necessary, I have included the various alternative names.
Smoke, shaded and tipped are all forms of tipped colouration – the colour is restricted to the hair tip while the shaft is either white/ivory (silver series) or golden (golden series). Shading causes the normally yellow-brown agouti band to be both lighter in colour and wider, starting closer to the root and ending nearer the hair tip than in tabby cats. The tipping colour is known as the top-colour, while the pale colour of the hair shaft is known as the undercolour. These patterns are most striking on the eumelanistic colours (black, blue, chocolate, cinnamon, lilac), because of the contrast between pattern colour or top-colour and the background or undercolour. Shading and silver also occurs in reds and creams which are sometimes termed cameos.
Chinchilla (also known as “shell”) is the lightest tipping. Here, only the hair tip is coloured and the hair shaft is silver. This gives the cat a sparkling appearance. For many cat fanciers, the Chinchilla Persian Longhair (Silver Chinchilla) is the epitome of the tipped cats. It has black tipped fur on a white undercolour. The best known shorthaired equivalent is the Burmilla, part of the Asian group. Because Chinchilla cats are genetically tabby, faint tabby markings can sometimes be seen on kittens. In shorthairs, this pattern is known as “tipped”.
The next degree of tipping is “shaded”. The colour extends further along the hair shaft, usually about half way. The colour is darkest on the back, creating a mantle of shading. Shaded silvers are the “black” form; but the shading can be a variety of colours. Shaded Silver lies between the extremes of Silver Tabby and Chinchilla and is commonly produced by mating a Silver Tabby to a Chinchilla. The amount of tipping is variable, ranging from a poorly-defined Silver Tabby to a dark Chinchilla.
Smoke is heaviest degree of tipping. The pale undercolour is reduced to a small band near the hair root. A smoke longhair often appears to be solid coloured with a pale ruff or frill. In shorthairs, smoke varieties appear solid colour until the coat is parted or the cat is in motion, exposing the undercolour.
In genetic terms, the silver tabby is identical to the silver undercoated cats but the pattern is dissipated due to the restriction of pigment to the tips of the hairs. Silver tabbies occur in ticked, classic, mackerel and spotted patterns which are described in Striped and Spotted Cats.
EARLY TIPPED AND SHADED CATS
The first chinchillas, shaded and smoke cats were Persian Longhairs with black (less frequently blue) tipping or shading on a near-white undercoat. These were the Black Smoke, Chinchilla (also known as the Self Silver) and the Shaded Silver. Early Chinchilla and Shaded Silver cats were derived from silver tabbies and were less well differentiated than their modern counterparts – some early Chinchillas might today be classed as poorly defined Shaded Silvers; some also had distinct tabby markings. Orange-eyed Shaded Silvers were originally preferred and are now known as Pewters or Pewter Tipped. For a while the Masked Silver was bred – this was a Shaded Silver Persian with darker face and paws.
Silver-undercoated Persians appeared very early on in the days of the cat fancy. Smoke Persians were described as far back as the 1860s and were believed to result from mating between blacks, blues and whites. In 1872, Weir described a cat as “a beauty was shown at Brighton, which was white with black tips to the hair, the white being scarcely visible unless the hair was parted.” The Smokes soon got a class of their own and their numbers rapidly increased. In Britain, dark Smokes are preferred, while American cat fanciers seemingly prefer lighter colour cats.
At the British National Cat Show in 1879, one of the entrants was described as “a strangely graduated grey”. Since the Smoke was already familiar, this was most likely a Shaded Silver.
The origin of the Chinchilla Persian as a breed lies in a female cat called Chinnie, born in 1882. Silver Tabbies and Black Smokes were already known at that time. Chinnie was probably either a Silver Mackerel Tabby or a Spotted Tabby Longhair (the spotted pattern is dissipated by the long hair) and would have had weak markings (heavy by modern standards). Her exact ancestry is unknown though it includes prize winning grandparents on one side and a stray tomcat on the other. Chinnie was evidently unusual enough for interested parties to want to breed similar cats from her. She was mated to Fluffy I who was a very pure Silver with undecided tabby markings” (might also have been Chinchilla).
Sadly, many of Chinnie and Fluffy I’s offspring died or strayed, and Fluffy I himself vanished in 1886. However one of their descendants, Beauty, was mated to a Smoke and produced the first recognisable Chinchilla in Champion Silver Lambkin who practically set the standard for the breed. The Chinchilla was recognised (got its own class) in 1894. Beauty continued to produce kittens and her descendants were mated to blues, silver tabbies and others. Blotched tabby, mackerel tabby and dilution were introduced into the gene pool from those very early days. Both tabby patterns can be seen in newborn kittens.
In 1903 Frances Simpson described Chinchilla shading as “a short of bluish lavender to the tips of the coat”, and “delicate tips of silvery-blue”. Breeders of the time describe it as “palest silver, lavender tint and lighter – in fact practically white – at the roots ” and “pure silver of a bluish tinge”. In 1907, the Chinchilla was also known as the Self Silver “A good self-silver has fur that is white at the roots and shades softly to a faint grey at the tips. The colour is rather that of old-fashioned silver lustre ware than of modern silver. The ideal self-silver must have neither markings nor shadings, nor must there be any black tips to the hair, either oh the back of in the tail or elsewhere”. Only in 1930 did the standard refer to the tipping as “black”.
Early Chinchillas had a range of levels of tipping and some confusion as to how much tipping was ideal. Orange eyes were preferred and in 1895, “Fur and Feather” carried an article regarding a green-eyed Chinchilla, “It is useless to think of exhibiting her on account of her green eyes”. Green eyes later became a standard – and distinctive – feature of Chinchillas.
In 1900 the Silvers class was split into Silver Tabbies, Chinchillas (light tipping) and Shaded Silver (heavy tipping). Then, as now, there were many cats which fell somewhere between tipped and shaded, plus different judges had different ideas as to where the line should be drawn. The same cat was sometimes rejected from both classes (due to different judges’ opinions) or was sometimes entered into both classes and won in both! The Chinchilla and Shaded Silver classes were combined to prevent confusion.
In 1926, after a curious cat (“a mixture of colours”) owned by Mrs Boutcher won the Any Other Colour class, Lord Sylvester suggested the starting of a new breed called “Marked Silvers”. The suggestion was not taken up. The cat was likely a silver tabby or shaded silver with markings of some colour other than black. In 1927, HC Brooke commented that some 50 years previously, there existed a pretty variety of short-hair tabby that was, in 1927, quite extinct. The ground colour was a creamy tint and the markings were always rather narrow and were reddish-brown. Since “sandy-coloured” or “lemony” red tabbies were frowned upon by cat fanciers, quite possibly this was a red-silver tabby. Red and cream Chinchillas appeared in the USA in 1934 through breeding Silver Chinchillas to Red Self Persians.
In 1951, Soderberg wrote wrote that the Chinchilla was unsuited to living in industrialised town! “It is a light-coated cat which is perhaps hardly suitable to the soot and grime of large industrial towns, but it is doubtful whether it needs much more attention than its darker-coated fellows.”
In the 1990s, breeders were concerned that Chinchilla cats were becoming ultra-typed like other Persians. Traditionally, the Chinchilla retained the longer muzzle. In America this resulted in a new breed classification, the Sterling, for the traditional-type Chinchillas. Older-style Chinchillas are more popular with members of the public, but the showbench Chinchilla seems to be moving inexorably towards the squashed-in look of other Persians. Outcrossing to other, already ultra-typed, Persian varieties is losing the old Chinchilla look. The photos below show cats of both types.
The Burmilla is a tipped silver cat of Asian/European Burmese type. Burmillas arose in 1981 as a result of an accidental mating of a lilac Burmese female and a Chinchilla male. This produced four Black Shaded Silver kittens of Burmese type and with a short, dense coat. The following year, there was a planned mating of a Blue Burmese female with the same Chinchilla male. These were the founding cats of the Burmilla variety although there have been a number of Burmese-to-Chinchilla matings since then in order to widen the gene pool. The Burmilla was recognised by FIFe in 1994. Although a relatively young breed, it is already extremely popular. In addition to the Burmilla there are also Asian Smoked and Asian Shaded Silver cats in a variety of different top colours.
A slightly different form of tipped fur is found in the Chausie, a breed derived from hybridising F chaus (Jungle Cat) with the domestic cat. Black Chausies with silver tipped fur occur and this is belived to be a form of black agouti rather than smoke/shaded or chinchila.
THE EARLY COLOURS
Tipping is not restricted to black. It can occur in any of the solid colours. The naming convention is given in the table below. Red on silver and cream on silver are also early developed colours and hence have a number of synonyms! The term “shell” was used to describe the cat having a shell of colour rather than a solid (to-the-roots) colour. “Cameo” described the type of red – similar to the colour of old cameo necklaces – with “Cream Cameo” (pictured below) simply meaning a paler form of this.
The tortoiseshell pattern can also occur on a pale undercoat, giving us the Tortoiseshell Chinchilla (Shell Tortoiseshell, Silver Tortoiseshell), the Shaded Tortoiseshell (Tortoiseshell Shaded Silver) and the Smoke Tortoiseshell, (Tortoiseshell Smoke). Tortoiseshell tabby (patched tabby) also occurs on the silver undercolour e.g. the Silver Patched Tabby (Silver Tortoiseshell Tabby).
THE EARLY COLOURS AND A CONFUSION OF NAMES
Full colourChinchilla = Silver/Silver Chinchilla (shorthair)
= Tipped/Black Tipped
Tortoiseshell Silver Tabby (Patched Silver Tabby)
Silver Ticked Tabby (Usual Silver Abyssinian/ Somali)Red Chinchilla = Shell Cameo/Red Tipped
Red Shaded (Silver) = Shaded Cameo
Red Smoke = Smoke Cameo
Red Silver Tabby = Cameo Tabby
Red Silver Tortoiseshell/Tortoiseshell Tabby
Red Silver Ticked Tabby (Red Silver Abyssinian/Somali)Broken Full ColourTortoiseshell Chinchilla = Shell Tortoiseshell/Silver Tortoiseshell
Shaded Tortoiseshell = Tortoiseshell Shaded Silver
Smoke Tortoiseshell = Tortoiseshell SmokeDiluteBlue Chinchilla/Blue Tipped
Blue Shaded Silver
Blue Silver Tabby
Blue Silver Tortoiseshell/Tortoiseshell Tabby
Blue Silver Ticked TabbyCream Chinchilla = Shell Cream Cameo
Cream Shaded (Silver) = Shaded Cream Cameo
Cream Smoke = Smoke Cream Cameo
Cream Silver Tabby = Cream Cameo Tabby
Cream Silver Tortoiseshell/Tortoiseshell Tabby
Cream Silver Ticked TabbyBroken Dilute ColourBlue Cream Chinchilla = Shell Dilute Tortoiseshell
Blue Cream Shaded = Shaded Dilute Tortoiseshell
Blue Cream Smoke = Smoke Dilute Tortoiseshell
THE NEWER COLOURS
Luckily the newer colours follow a general formula without too many confusing synonyms e.g. Chocolate (Chestnut) Chinchilla, Lavender (Lilac) Shaded Silver etc.
[colour-name] Silver Tabby
[colour-name] Silver Tabby-Tortoiseshell ([colour-name] Silver Patched Tabby)
[colour-name] Silver Ticked Tabby, [colour-name] Silver Abyssinian/Somali
Some of these colours have probably turned up historically, but have not been recognised as distinct colours. For example, some early tipped, shaded and smoke cats were described as poorly coloured. “Poorly coloured” Blue Smokes were very likely Lilac Smokes, a colour not recognised or understood at the time.
The Golden series is also relatively recent and is still uncommon:-
Golden Chinchilla, [colour-name] Golden Chinchilla
Shaded Golden, [colour-name] Shaded Golden
Golden Smoke, [colour-name] Golden Smoke
Golden Tabby-Tortoiseshell (Golden Patched Tabby)
Golden Ticked Tabby, [colour-name] Golden Ticked Tabby
Golden tabbies are derived from Chinchilla/Shaded Silver cats. Because the Inhibitor gene is dominant, a shaded/tipped cat might carry a hidden recessive form of that gene. If two recessive carriers are bred together, there is a good chance that some kittens will inherit two copies of the recessive gene, giving rise to a Golden. They cats are different from other tabbies, being brighter in colour due to wider colour bands on the hair shaft.
Smoke is caused by the combination of the dominant Inhibitor gene with the recessive Non-agouti gene. The Inhibitor gene gives rise to a pale undercolour. The extent of this undercolour is variable and the smoke can be described as light, medium or dark depending on the amount of top-colour (tipping, known as “veiling” in smokes) and the extent of the pale undercolour i.e. how far the pale colour extends along the hair shaft. Occasionally a Smoke can be so light in colour that on visual inspection it is Shaded cat (e.g. a very light Black Smoke resembling a Shaded Silver), although true Shaded cats have the Agouti gene, not the Non-agouti gene.
In smoke cats, the undercolour varies from almost white to a bluish grey. Cats with darker undercolours may look self coloured, especially in black cats. It is possible to have a cat which is genetically a smoke, but which is visually solid black! The heavy tipping combines with a very narrow white hair base so that the smoke effect is lost. This variation in the relative amounts of undercolour and top-colour appears to be due to modifier genes and mirrors the way in which modifier genes act on shaded silvers to produce both shaded cats and chinchillas (and often in the same litter). Some smokes, known as overlaps, never develop the silvery undercoat and only prove to be genetically smokes when bred.
Smoke kittens sometimes show faint tabby markings (as seen in the photo on this page). Young smoke Persians look almost solid in colour except for a silver tracery (clown lines) where the agouti areas would appear in a tabby. Not all kittens have clearly visible clown lines, but those that do have them tend to develop more striking adult coats. In adults, the presence of clown lines is penalised. The smoke effect is more obvious in longhaired cats and is not restricted to black smokes. Other colours can be combined with the Inhibitor gene to produce blue smokes (black + dilute modifier + Inhibitor gene), chocolate smokes, lilac smokes and red smokes. Black, blue and red are the longest established and best known varieties. Some of the “newer” colours have appeared historically and were probably dismissed as “poorly marked” individuals in one of the then known colours.
The Red (Cameo) Smoke is produced by a combination of the Inhibitor gene and the gene for red. These have a red/orange tipping on a whitish undercolour. Because of the way in which red colour is inherited (Tortoiseshell and Tricolour Cats), the males are red, but the females may be either red or tortoiseshell.
The Non-agouti gene has no effect on the red colour as it is produced by a different pigment. This means that the difference in appearance between Red Smokes and Red Shaded Silvers/Red Chinchillas is not due to the cats having the Agouti or Non-Agouti gene as it is with the other colours. The Agouti gene affects non-red colours such as black, blue, chocolate etc so it does make a difference in whether the non-red areas of tortoiseshells turn out as smoke (Non-agouti) or as silver tabby, blue silver tabby etc (Agouti).
The difference between Red Smoke, Red Shaded Silver and Red Chinchilla appears to be due to the Inhibitor gene causing the pale undercolour and various modifiers dictating how far along the hair shaft the undercolour and top-colour extend respectively.
The Cream Smoke, Cream Shaded Silver and Cream Chinchilla are due to the presence of the dilution gene in addition to the red gene. In the tortoiseshells, this additionally turns a red/black tortoiseshell into a blue smoke tortie or a blue silver tabby tortie.
Shorthaired solid colour cats tend to have have ghost tabby markings which are particularly visible in kittens. As a result of ghost markings, Smoke shorthairs may appear to be Smoke tabbies. Hence the Black Smoke Egyptian Mau has visible spots on a Smoke background. According to Phyllis Lauder’s book “The British, European and American Shorthair Cat” (1981), the Smoke factor can turn up in unexpected places. Lauder had a Blue Cornish Rex with underfur of the ash-white colour proper to a Smoke. When the cat was 2 years old, she noticed that the fur behind his ears looked silver. At the time, he could not be described as Smoke according to the standards for that colour (which demanded a light silver fril; and ear tufts and an ash-white undercoat tipped with blue), but he was nevertheless a Blue Smoke. The appearance of the smoke factor was not always welcomed by breeders. In particular, there were complaints that Red and Cream longhairs showed an undesirable degree of white in the undercoat.
Silver tabby is also caused by the dominant Inhibitor gene, but this time in combination with the dominant Agouti gene. Silver tabbies have a silvery background colour with a tabby pattern overlaid on it. Silver tabbies in the random breeding population are prone to tarnishing – the appearance of a yellowish or rusty hue. The Inhibitor gene seems eliminate the yellow pigment in the agouti (ticked) hairs of the background colour, but does not affect the non-agouti areas (the markings). In longhairs, the silver pattern is diffused by the hair length although residual striping may be seen on the legs and face.
The growing popularity of the Chinchilla Persian was at the expense of the silver tabbies which almost vanished (although World War 2 also caused many breeds to go into serious decline). In 1951, Soderberg wrote “Silvers – this breed has almost disappeared, and at the present time there are only very few breeders who are attempting to bring it back to the popularity which it possessed at the beginning of the century. Admittedly it is a difficult breed, and the only specimens which one now sees are lacking in type. A really good specimen could expect to win premier honours at a show, and it is well worth attempting to produce such a “flyer”. Although the Silver Tabby is definitely one of the neglected breeds, it would be a thousand pities if it were allowed to sink into oblivion.”
Silver Mackerel Tabby
Silver Classic Tabby
The best known silver tabbies are the shorthaired black versions (widely used in advertising), simply called Silver tabbies. These have black markings on a silver undercoat (as shown in the photo; this cat has some tarnishing). Other silver tabbies are prefixed by the name of the marking colour e.g. Blue Silver Tabby, Chocolate Silver Tabby, Lilac Silver Tabby, Cinnamon Silver tabby and Fawn Silver Tabby. Pewter Tabbies are now more correctly known as Blue Silver Tabbies.
There are also Red Silver Tabbies (Cameo Tabbies) and Cream Silver Tabbies (Cream Cameo Tabbies) which have red markings and cream markings respectively on a silvery background.
The Inhibitor gene has also been introduced into Abyssinians and Somalis to create silver-undercoated varieties of ticked tabby. These are popular in Britain, but less well known in the USA. The Alaskan Snow Cat has the silver ticked tabby pattern, but has a more rounded shape.
The Silver Tabby has an identical genetic make-up to the Shaded Silver and Chinchilla. The amount of pigmentation depends on minor sets of genes (polygenes).
SHADED SILVER AND CHINCHILLA (TIPPED)
Shaded Silver and Chinchilla are also caused by the dominant Inhibitor gene in combination with the dominant Agouti gene. The underlying tabby pattern is demonstrated by chinchilla kittens which appear silver tabby until the hair grows long enough for the white undercolour to be properly developed. As the hairs become longer, the tabby pattern is diffused and only the very tips of the hair are coloured, producing a sparkling effect. Occasionally a Smoke (Non-agouti) can be so light in colour that on visual inspection it is Shaded cat (e.g. a very light Black Smoke resembling a Shaded Silver); however it is different genetically.
The first silver chinchillas were developed from unsound or spoiled silver tabbies mated to lightly tipped smokes. Unsound or spoiled silver tabbies were those where the silver undercoat was evident at the base of the black hairs which formed the markings. Because chinchillas resulted from crossings to smokes, it was thought that a single factor (what would now be called a gene) was responsible for chinchillas, shaded silvers and smokes. There are light, medium and dark smokes and light smokes were sometimes mistaken for shaded cats and bred with chinchillas.
Selective breeding has increased the amount of undercolour and reduced the extent of top-colour. The long fur emphasises the undercolour and prevents the hair tips from forming a recognisable tabby pattern. Some tabby effects may still be seen in body areas with shorter fur: the face and lower legs. The longer the fur, the better the pattern is dissipated, hence shaded shorthairs are at a disadvantage compared to the longhairs. Although some Shaded shorthaired cats have a tabby pattern at birth, this should be dissipated by hair length in adulthood. Sometimes the tabby pattern persists into later life and is considered a serious fault (or the cat is quietly reclassified as a tabby). There are likely to be various modifier genes which further disperse the tabby pattern and reduce the pigmentation of the hair shaft by creating wider bands.
The Shaded Silver and the Silver Chinchilla (usually known simply as Chinchilla with no colour qualifier) are the most familiar of these cats and the longest established. They are not the only colour variants though. The Blue Chinchilla is the dilute form of the Chinchilla and appears almost identical. Blue Chinchillas are most easily distinguished as kittens when the blue colour is less diffuse.
The Chocolate Chinchilla is also most easily identified in kittenhood. Adult Chocolate Chinchillas have dusky-brown or “off-black” tipping. Lilac Chinchillas, Cinnamon Chinchillas and Fawn Chinchillas are also possible.
The Red Shaded Silver and Red Chinchilla (and also Tortoiseshell Shaded and Tortoiseshell Chinchilla) are produced by a combination of the Inhibitor gene and the gene for red. The difference in appearance between the Red Shaded Silver and Red Chinchilla is due to modifiers acting on the extent of the undercolour and top-colour along the hair shaft. The Agouti gene affects non-red colours such as black, blue, chocolate etc so it does make a difference in whether the non-red areas of tortoiseshells turn out as shaded/tipped (Non-agouti) or as silver tabby, blue silver tabby etc (Agouti).
The Cream Shaded Silver and Cream Chinchilla are due to the presence of the dilution gene in addition to the red gene. In the tortoiseshells, this additionally turns a red/black tortoiseshell into a blue smoke tortie or a blue silver tabby tortie.
In 1969 or the early 1970s, Mrs Worthy of Hertfordshire bred some unusual Devon Rex twins whose white coats were “sprinkled exotically with lilac highlights”. The only photo is a black and white one, showing the cats as having darker noses (not surprising, since the hair is shortest on the nose). These would seem to be lilac tipped, though by all accounts they were somewhat unexpected!
The Chinchilla’s sparkling looks mean it is often associated with luxury, quality and class; Chinchillas are therefore used in advertising products which want to appear a cut above the rest.
During the course of breeding Shaded Silvers and Chinchillas, what looked to be orange-eyed Shaded Silvers appeared. These were known as Pewters or Pewter Tipped. Some of the earliest Pewters may have been genetically blue (grey) rather than black or may have been light Smokes. Still not common compared to Chinchillas and Shaded Silvers, the modern Pewter has heavier tipping than the Shaded Silver resulting in a darker mantle.
The first Pewters were bred sometime in the 1970s and found in the “Any Other Colour” classes along with other Shaded cats of then unrecognised colours (some of those cats are now recognised as Chocolate Shaded and Lilac Shaded). The Black Pewter gained Championship Status in 1986 in the UK. Still considered by some to be a poor relation of the Shaded Silver, the Pewter remains comparatively rare.
In the late 1890s and early part of the next century, orange eyes were standard for Chinchilla and Shaded Silver cats. Green eyes, now a prominent feature of these cats, were actually considered a fault in those days! Those with a sense of history are pleased to see the ancestral eye-colour being bred again and Blue Pewters have also been recognised.
The term Pewter Tabby has been used historically to describe the Blue Silver Tabby.
Resembling the Shaded Silver in all respects apart from dark mask and dark legs, the Masked Silver is believed to be a “light” Black Smoke i.e. a Non-Agouti cat with the Inhibitor gene. On the body, the top-colour is reduced to no more than half the length of the hair producing the visual effect of a Shaded Silver. On the face and legs, however, the top-colour extends further along the hair shaft, indicating the cat’s true type. It is more apparent in modern Shaded shorthairs although some very attracted Masked Silver Persians have been bred in the past.
Martine Sansoucy of Butterpaws LaPerms has seen a number of masked silvers and notes that they appear to be smokes rather than shaded silvers. Butterpaws BC The Crow, known as “Cairo” is a black smoke that meets the general description of a masked silver. As can be seen from the photo, the different textures of fur on the face and the body give the impression of a masked cat with the black colour being more intense on the straighter fur.
Historical Masked Silver.
Masked Silver (black smoke) LaPerm.
Some authors have written that the masked silver dates back to 1900, but were probably referring to the shaded silver, a variety not recognised in Britain at the time and considered to be a badly bred chinchilla. According to Milo Denlinger in 1947, “Masked silvers are a new variety and very few are bred.” Denlinger went on to describe the variety: “The ideal masked silver is a very beautiful animal; in colouring or, I should say, marking, they should resemble the Siamese Cat; that is to say, they should have a black mask, or face, black feet, and legs. The body should be as pale a silver as posible.” The eyes were to be deep golden or copper. Several authors have observed that the description of the masked silver resembles that of the Siamese. The Masked Silver was also described by Mery and others in the 1960s.
Before the Shaded and Smoke cats patterns were known to be genetically distinct, this was regarded as a sub-type of Shaded Silver and a number of attractive Masked Silver Persians were bred. Some were described as having darker bodies (mantles) than Shaded Silvers”.
EARLY GOLDEN CATS – SABLES
Mirroring the silver series, there is the newer and less common golden series. One of the most famous early chinchillas was called Silver Lambkin, and it seems likely from descriptions at the time that he gave rise to both silver and golden kittens. Unknown to early breeders who did not have the benefit of genetics knowledge, where there are Chinchilla Persians, Silver Tabby Persians and Silver Tabby Shorthairs there would usually be Golden and Golden Tabby cats too. These were generally considered , known as “brownies” and discarded, though some Golden Tabbies no doubt found their way into the Brown Tabby Class since early writers differentiated between the “Brown Tabby” and the “Sable Tabby”.
The GCCF studbook of 1925 listed a “sable chinchilla” male called Bracken, whose parents were Caiville (male) and Minetta (female). Bracken appears to have been an early Golden Persian and apparently had a chinchilla female littermate. An influential “silver” (Chinchilla) female, Recompense of Allington, was born from another mating of Caiville to Minetta and there is a 75% probability that Recompense carried the Golden gene which popped up in Chinchilla descendants later on. Evelyn Buckworth-Herne-Soam’s 1933 book included a chapter on the Brown Tabby Longhair. She commented on the very successful Brown Tabby Longhair of 1896, Champion Birkdale Ruffle and also on a much later “rich sable colour” cat called Treylstan Garnet and referred to the colour class as “brownies”, then the term for the brown tabby (as opposed to “silvers”).
In 1927, Mrs Sydney Evans placed her Longhair Sable at stud. The cat was acquired from Mrs Jourdain who knew of several cats of that variety and hoped that they might become better established. All were bred from Chinchilla stock. Sable was excellent in type and had a good sable coat with black tips (called ticking, but not to be confused with the Abyssinian) along the spine and on the tail, head and paws. His eyes were emerald green.
Assuming that the “Sable Tabbies” of history were in fact Golden Tabbies, the following descriptions of Sables from around 1903 give an insight into the early history of the golden series.
The 1903 “Book of the Cat” stated: “There is a distinct kind of brown tabby, which may better be described as sable. These cats have not the regular tabby markings, but the two colours are blended one with another, the lighter sable tone predominating. At the Crystal Palace Cat Show of 1902 the class was for brown tabby or sable. I was judging, and, considering the mixed entries, I felt that markings must not be of the first importance, and so awarded first and second to Miss Whitney’s beautiful sable females, the third going to a well-marked though out of condition brown tabby. … These sable marked cats are rare, but still more beautiful would be a cat entirely of the one tawny colour – a self sable, without markings. “The most suitable factors to obtain this colour,” so writes Mrs Balding, “would probably be tortoiseshell-and-sable tabby, as free from marking and as red in ground colour as possible. A cross of orange, bright coloured and as nearly as obtainable from unmarked ancestors, would be useful. Some nine years ago I purchased a dimly marked bright sable coloured cat, ‘Molly,’ shown by Mrs Davies at the Crystal Palace, with a view to producing a self-coloured sable cat; but ‘Molly’ unfortunately died, and I abandoned the ide The nearest approach to a self-sable I have ever come across was a cat I obtained for the Viscountess Esher, which had, alas! been neutered. He was almost unmarked, and of the colour of Canadian sable, with golden eyes – a most uncommon specimen.”
Frances Simpson wrote: “For sables we, of course, go to the Birkdale strain. I remember the incomparable “Birkdale Ruffie” in his full glory at the Crystal Palace – a mass of red-brown fur, of the style of “Persimmon Laddie,” but with more distinct markings and a very keen, almost fierce expression; in fact, he looked like a wild animal! Then “Master Ruffie” appeared as a kitten, and later as a mild edition of his sire. From this celebrated strain Miss Whitney’s lovely sables are descended. … the brown tabby and sable, though often classed together, must not be confounded. The brown tabby is supposed to be the common ancestor of all our cats, and hence the tendency to revert to that colour. … They appear in very unexpected places – in a litter of chinchillas or blacks, or among our oranges, and sometimes where no brown ancestor can be traced. … As regards the sables, I may remark that they are late in maturing and do not acquire their marvellous colouring till about the second year .” (She also remarked that sable tortoiseshells existed)
Miss Southam described Birkdale Ruffie in Frances Simpson’s The Book of the Cat: It was at the West of England Cat Show in 1894 that ‘Birkdale Ruffie’ scored his first real success winning two first prizes in the open and novice classes and two specials. Here at last his beautiful sable colouring, his dense black markings, and wonderful expressive face were appreciated. The year 1896 was the occasion of his sensational win at the Crystal Palace show. He simply swept the board, carrying everything before him – first prize, championship, several specials, and the special given by the King (then Prince of Wales) – for the best rough-coated cat in the show. Again, in 1897, he was shown with great success at the Crystal Palace, winning first prize, championship and special. This was the occasion of ‘Birkdale Ruffie’s’ last appearance before the public, as it was during the following month my sister was taken dangerously ill, and for this reason his pen at the Brighton show was empty. After her death we determined to subject him no more to the trials and discomforts of the show pen so ‘Ruffie,’ who was now seven years old and a great pet, both for his own sake and that of his mistress, only too gladly retired […] watching his facsimile, his little son ‘master Ruffie,’ growing up more beautiful each day and ready to take up the thread of his father’s famous career in the exhibition world.
Into the latter ‘Master Ruffie’ made his debut without any of the numerous anxieties encountered by his celebrated parent. The way was paved for him, and when he appeared at the Crystal Palace show in 1899, in all the full glory of his youth and beauty, it was difficult for the judges to realise that it was not their old favourite who was now confronting them through the wires. ‘Master Ruffie’ has only been shown on two occasions – in 1897 as a kitten, and in 1899 at the Crystal Palace, when he returned home with his box literally filled with cards, his winnings including three first prizes, four specials, and a championship. I am sorry we can manage to get no really good photo of ‘Master Ruffie’ … steadfastly refuses the face the camera. Again and again the button is pressed in vain, and only the glimpse of a vanishing tail upon the negative is all we have to show as ‘Ruffie’s’ portrait! [Master Ruffie] is a very cobby little fellow, being perhaps shorter in the legs, which makes him appear to be a somewhat smaller cat than his father. ‘Birkdale Ruffie’ was noted for the extreme beauty of his expression; he had certainly one of the most characteristic faces ever seen in a cat, and his son inherits the same. The former was constantly the subject of sketches in the illustrated papers, those by Mr Louis Wain being especially lifelike. Some of ‘master Ruffie’s’ descendants are, I believe, in the possession of Miss Witney, and have met with great success in the show pen.”
Miss Witney wrote “‘Brayfort Fina’ is, I may say, a sable tabby, being particularly rich in colour all throughout – indeed, more often of an auburn tan than brown. …’Fina’ was bred by Miss G Southam, and is by ‘Master Ruffie’ ex ‘Bluette,’ her sire being a son of the famous ‘Champion Birkdale Ruffie.’ [In 1902 'Fina' took first] at the Bath Specialist Show in the same year, where her gorgeous colouring was called in question and an unsupported protest was made that she was dyed!
THE GOLDEN SERIES
Until relatively recently some breeders believed goldens to be the result of more recent mis-matings between chinchillas and self Persians. At present the genetics of the golden series are not fully understood. The naming convention is below. Being a newer variety, the naming convention is standardised hence [colour-name] indicates the tipping/shading colour e.g. Blue Shaded Golden, Tortoiseshell Golden Chinchilla. Where a cat is described with no addition “colour-name” the tipping/shading/tabby etc is assumed to be black. The Golden Tabby is equivalent to the Silver Tabby with distinct markings on a golden background.
Golden Chinchilla, [colour-name] Golden Chinchilla
Shaded Golden, [colour-name] Shaded Golden
Golden Smoke, [colour-name] Golden Smoke
Golden Tabby-Tortoiseshell (Golden Patched Tabby)
Golden Ticked Tabby, [colour-name] Golden Ticked Tabby
Golden tabbies are derived from Chinchilla/Shaded Silver cats. Because the Inhibitor gene is dominant, it is believed that a shaded/tipped cat might carry a hidden recessive form of that gene. If two recessive carriers are bred together, there is a good chance that some kittens will inherit two copies of the recessive gene and this was believed to be the cause of golden chinchillas, shaded goldens and golden smokes. This theory is shown below; the “silver agouti” means a tipped or shaded cat.
|I (Inhibitor)||i (non inhibitor)|
|i (non inhibitor)||Ii
(Non-silver i.e. golden)
Non-silver cats with the agouti gene are known as Golden Tabbies, Chinchilla Golden or Shaded Golden depending on whether they have the tabby pattern, shaded pattern or chinchilla tipping. These cats are different from other tabbies. They are much brighter in colour due to wider colour bands on the hair shaft. The hairs are almost wholly golden with a darker tip and a pale or greyish undercolour near the base of the hair.
The variability of chinchilla and shaded cats, and the existence of golden series cats, has led breeders to hypothesise the existence of a separately inherited recessive “Wide Band” gene that would brighten brown tabbies to golden tabbies and brighten shaded cats to chinchillas (tipped cats). This affects the banding pattern of individual hairs, producing a wider-than-normal band of bright colour. Wide Band would determine the width of the hair shaft colour (the undercoat) between the pigmented tip and the follicle. The presence or absence of the Inhibitor gene does not affect Wide Band since Golden Shadeds lack the Inhibitor gene, but have a shading pattern comparable to Silver Shaded cats. According to this theory, golden series cats would not be golden due to a recessive form of the inhibitor gene, they would be golden due to the separately inherited wide band gene.
Still others consider it more likely that the colour is caused by multiple interacting genes (polygenes) producing a combined effects.
These photos from Lisa Wahl (www.blindcougar.org) show golden tabbies. Some have red markings and others have brown markings, but the background colour is bright golden. The cats came from a breeder who had died, leaving behind a line of golden “Maine Coon type” cats she had developed from barn cats, plus extensive breeding records. Some of the 50 cats rescued have very red undersides, and black paw pads.
LATE COLOUR CHANGE “GOLDENS” & THE BLACK MODIFIER GENE
Over the years, there have been accounts of pure silver Persian kittens turning to a pale golden colour as they mature. This often began with yellowish “tarnish” or cream spotting appearing in the coat of a shaded silver or chinchilla cat. Reddish hairs first appeared on the spine, face or paws, and progressed through a yellowing of the undercoat. Chinchillas derived from chinchilla-to-chinchilla matings sometimes exhibited reddish or golden hair along their spines which was attributed to incomplete dominance of the golden gene “breaking through” in the coat. Some silver kittens were, when 2 or 3 years old, very definitely pale golden adults. Offspring born to such cats were born as silvers, showing the “golden” cat was genetically a silver, but some of those offspring also had a tendency to turn golden at about 2 or 3 years old.
Silver and chinchilla cats have been selectively bred to eliminate (as far as possible) polygenes that would modify the colour’s purity. The silver should, therefore, be devoid of genes that cause cream, yellow and red pigment. Yellow denotes the technical term for the pigment granule which produces all of these colors. Polygenic complexes have plus and minus polygenes that influence the trait. Diligent breeding resulted in accumulations of either plus or minus polygenes in a specific breed or colour. However, these polygenes are carried on different chromosomes and inherited independently of each other.
In silvers, the inhibitor gene means the round granules of eumelanin (black) are absent from most of the hair shaft and are clumped near the tip. Being incompletely dominant, the effect ranges from shaded silver through to tipped (chinchilla). In normal goldens, the granules of the yellow pigment phaeomelanin are likewise influenced by the inhibitor gene. However, the silvers that turn into goldens don’t have any phaeomelanin. Instead, these “pseudo-goldens” turned out to have an additional mutation that caused their eumelanin granules to be elliptical rather than round and to show as a beige or pale golden colour. These mutant granules are not completely eliminated from the hair shaft, but are smeared along it, causing a pale golden undercoat. They are also clumped at the tip to give the shaded or tipped effect.
Eumelanin is usually described as “black”, but is actually a deep brown (sepia) that appears black to our eyes. As the eumelanin granule becomes elongated, it appears paler and more reddish-brown or dark-yellowish-brown. The concentration of the mutant eumelanin granule on the hair shaft gives colours ranging from copper-brown through apricot to reddish honey, all with darker tips. The mutated eumelanin gene has been described as a “late colour change” gene for obvious reasons. Its mode of inheritance not fully understood. It is also possible that some apparently golden-from-birth Persians may be pseudo-goldens and can have silver kittens – generally considered an impossibility as silver is dominant over normal golden and cannot be carried as a recessive (though silver can reoccur as a spontaneous mutation).
A “late colour change” mutation, again causing an end result of golden, has been observed in Norwegian Forest Cats. The Black Modifier gene, found in Norwegian Forest Cats, brightens black or blue areas of the coat to Amber (apricot-to-cinnamon colour) and Light Amber (pale beige). At birth, kittens appeared to be black or blue, and lightened to Amber or Light Amber respectively. Amber has also occurred in conjunction with silver: the kittens were born as poorly coloured black-silver or blue-silver tabbies whose tabby ghost-markings faded as they matured and their colour became a bright apricot to cinnamon colour with dark brown paw pads and nose leather with no black rim (the black rim is characteristic of silvers). Their original birth colour could be seen only on the back and tail.
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. 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.
MORE-THAN-TIPPED BUT NOT-QUITE-SHADED CATS
The criteria for each degree of tipping is an ideal and there are many cats which visually fall between two ideals.
Although the genetic combinations are different; smoke = Inhibitor + Non-agouti while shaded/tipped = Inhibitor + Agouti, the variability of expression results in cats which seem intermediate in colour. This is a “two gene theory” where the two genes involved are the Inhibitor and the Agouti/Non-agouti genes. There are pet quality cats where the tipping is too heavy for it to be a well marked chinchilla, but too light for it to be a shaded silver. There are also shaded silvers dark enough to resemble the genetically different “light” black smoke. These differences are caused by various polygenes. This “two gene” theory is the one to be found in modern feline genetics texts. Before this interaction was understood, there was believed to be a recessive “chinchilla gene” which controlled the degree of tipping.
Before the genetics of these cats was well understood, the apparent continuous gradation between chinchilla through to smoke would have resulted in some matings between mis-identified cats. For some while, it was believed that Smoke, Shaded and Tipped were all variable effects of the same gene (or “factor” since the term “gene” was not in usage in the early days of cat breeding). This “one gene theory” seemed to be borne out by the fact that some Shaded cats were so dark as to be poorly marked Smokes, while Smokes occurred in a range of intensities from light (Masked Silver) through to dark (solid colour). And of course, the earliest shaded and chinchilla cats were seen to have come from mating tabbies with smokes.
In Tipped/Chinchilla and Shaded kittens, the tabby pattern may still be visible as it is the long hair which diffuses the colour. In Smoke shorthair cats, just as in many solid black cats, a tabby pattern is often still discernible in the form of ghost markings. This pet kitten appears to be a black smoke tabby and white (or a heavily marked shaded silver with white). In adulthood, the tabby markings will be obscured by his long fur. Smoke-and-white and Shaded-and-white are not colour varieties accepted by registries.
Those cats which meet neither the Chinchilla/Tipped nor the Shaded standard are still attractive pets.
GENETIC THEORIES FOR SHADED CATS AND SILVER TABBIES
The earliest theory suggested a Chinchilla gene which was a version of albino. Work by Keeler and Cobb seemed to indicate that the gene producing “silver” or “smoke” in cats was an allele of the same gene that produced the Siamese coat pattern i.e. a form of albinism. They described the effect of silver as and producing the following types of hair (1) all white, (2) all black (in dark silvers or smokes), (3) black hairs with white tips, (4) hairs with white and grey or black bands, and (5) white hairs with black tips. However, this would rule out the possibility of Shaded Sepia, Shaded Mink and Shaded Pointed colours. Since these colours have been shown to be possible in experimental breeding (even if not present on the showbench), the Chinchilla gene theory was obviously incorrect.
A second theory proposed a single dominant Inhibitor gene, but this could not explain the variations of shading. In addition, breeding demonstrated that Smoke cats were genetically different from Shaded and Chinchilla (Tipped) cats and not variable expression of a single gene.
The current theory, and even this may ultimately be disproved, is that there are at least two genes involved and that these interact to produce different effects. There are also a number of as yet unidentified polygenes which may influence the colour and pattern.
Originally, the Inhibitor gene was thought to work similarly to White. In white cats, either the melanocytes (pigment-forming cells) are absent or abnormalities in the cells means that pigment can’t be produced. The Inhibitor gene does not work this way.
In silver tabbies, the pigment cells produce far less pigment than normal. Pigment is laid down at the hair tip, but little is laid down on the hair shaft which appears silver or grey rather. If pigment was entirely absent, the hair shaft would be pure white. Sometimes the Inhibitor gene fails to completely block phaeomelanin (the red pigment) and the resulting breakthrough of reddish colour is known as “tarnishing”. Tarnishing can often be seen on the muzzles of random bred silver tabbies, but rarely on pedigree silver tabbies (a refinement which sets the purebred version apart from the random-bred version).
In Non-agouti (non-tabby i.e. solid colour) cats, the Inhibitor gene only lightens the undercoat area. Where it fails to completely block residual pigment production, the undercolour is grey rather than white.
In addition to the Inhibitor gene (not present in the Golden series), a silver cat may also have the Wide Band gene The existence of a “Wide Band” gene is disputed. If it exists, Wide Band determines the width of the hair shaft colour (the undercoat) between the pigmented tip and the follicle. The undercoat length varies, being narrow on the cat’s back and wider at the belly. It is believed that the presence or absence of the Inhibitor gene does not affect Wide Band since Golden Shadeds lack the Inhibitor gene, but have a shading pattern comparable to Silver Shaded cats. There may be polygenes which affect the undercoat width rather than a single Wideband gene; some ideas are mentioned in the section below.
Wide band is considered as either an effect (due to interacting genes) or as a gene. Leaving the exact mechanism aside, it can be treated as a dominant gene when looking at inheritance. If a non-agouti cat (self/solid cat) has dominant wide band (Wb), this will not show up unless it also has silver in which case it is a smoke. In tabbies, Wb may account for the different appearance of silver tabbies, shaded silvers and chinchillas (tipped). If a non-agouti cat has silver but has recessive wide-band (wb or narrow-band), it could account for the poor smokes and hidden smokes. Wide-band is noted to have an additive effect – one copy is wide band, 2 copies is even wider band. There may even be multiple alleles of wide-band.
While the Agouti gene permits the hairs to have bands of colour, separate genes for banding frequency, band width and band placement probably influence the banding pattern of the hairs. An ideal Shaded Silver hair would have a single broad band of pigment at the tip of each hair. Shaded Silvers have a mix of three patterns: a single broad band and wide undercoat; a few broad bands and wide undercoat or multiple thin bands (as seen in the background colour of Silver Tabbies).
Burmilla breeders who rarely saw tipped cats in early generations, but saw them frequently in later generations, even suggest that in addition to dominant wide-band there may be a second recessive “super wide band” gene for tipping. However these effects are equally attributable to inheriting either one or two copies Wb.
In goldens, wide band refers to the yellow banding of the hair shaft. Wide-band would have no effect on a non-agouti cat as the hair shafts are not banded. A eumelanin series cat (black/brown) can have the recessive form of inhibitor gene (golden), but doesn’t have true red pigment (phaeomelanin), so the undercoat is warm cream or apricot rather than bright golden. For that reason, it’s suggested that some poor quality silvers are really creamy goldens that give the illusion of having silver.
EFFECT OF OTHER GENES
There are probably other genes that influence the number and width of coloured bands on each hair and reduce or eliminate residual tabby markings on the chest, legs and sometimes tail. Yet other genes probably influence the sparkling appearance. In addition to the Agouti gene and Inhibitor (silver) gene, a Shaded cat may also have the Wideband gene (hypothetical) plus genes which influence the number and width of coloured bands on each hair and reduce or eliminate residual tabby markings on the chest, legs and sometimes tail. Yet other genes probably influence the sparkling appearance.
Some tipped and shaded silver shorthairs may have the ticked (Abyssinian-type) tabby gene in addition to the classic or mackerel tabby gene(s). This only shows up if matings of Shaded Silvers to Classic Tabbies unexpectedly produce ticked tabby kittens. Since ticked tabby masks out any other tabby pattern, it could only have been carried by the Shaded Silver parent. Tipped or Shaded Silver kittens born without a tabby pattern probably carry the ticked tabby gene, while those born with a discernible tabby pattern may lack the ticked tabby gene.
Breeder of Shaded Silver American Shorthairs, Carol W Johnson, suggested at least two modifier genes which affect ticked tabbies and which dissipate residual tabby markings in shaded shorthairs. She referred to them as Chaos and Confusion. A third gene. “Erase” was proposed by Cathy Galfo (working with Oriental Shorthairs) and appears to reduce or remove residual barring on the extremities. Currently, these names describe effects rather than actual genes.
Johnson noted that the each hair in a shaded cat differs in band number and width; ranging from solid colour and solid white through to multiply banded and singly banded. She termed this “Confusion” as it “unco-ordinated” the hair follicles to so that they produced different banding patterns to their neighbours. In contrast, Abyssinian-type ticked tabbies have even banding and relatively even colouration which stops abruptly at the belly (like a tide mark on a boat!). Shaded cats with high levels of Confusion (uneven band width) had a more mottled or “sparkling” appearance and a more gradual blending and fading of the colour from back to belly.
However, the confusion effect can be achieved with polygenes. Except for genes on X and Y chromosomes, each cell has 2 copies of each gene. The 2 copies might be identical or different and normally one is dominant to the other. Sometimes, e.g. when the genes are different but co-dominant, one copy is deactivated; this happens in foetal development. One cell might have activated the gene telling it to make 3 bands of colour while the cell next to it might have activated the slightly different copy of the same gene telling it to make 5 bands of colour. There might be a gene located elsewhere on the chromosome which, if switched on, override those genes entirely with an instruction to make a solid coloured hair! So while “Confusion” is a good name for the phenomenon on a visual level, a single Confusion gene seems unlikely.
In addition to Confusion, Johnson also hypothesised a rarer gene causing roan. In roan, solid white hairs are intermixed with normal hairs. This occurs in dogs (merle, roan) and horses (roan, flea-bitten grey). In Shaded shorthairs, “Roan” might result in Shaded Silvers so pale as be visually Chinchillas.
Johnson’s “Chaos” gene further disrupts the striped pattern by abnormally mixing ticked hairs into normally solid coloured regions (and vice versa). This effect is visible in the modified tabby pattern of the Sokoke. An mechanism for this was described by Australian Mist breeder Truda Straede who suggested a gene which disrupted a normal tabby pattern into a “finely divided tabby pattern” (Striped and Spotted Cats). Straede had never seen the Sokoke, but predicted the patterns existence based on her work with “small pattern spotted tabbies” and “large pattern spotted tabbies”. Chaos might eradicate residual necklaces and ghost striping in ticked tabbies and in Shaded cats.
Cathy Galfro proposed a separately inherited “Erase” gene, different to Confusion and Chaos, which removes residual markings from the neck, legs and tail of Shaded Oriental Shorthairs.
As detailed above, silver (the inhibitor gene) is dominant while the recessive (hidden) version is golden. If a cat is not silver, genetically it must be golden. The phenomenon of a non-silver cat producing silver offspring when bred to an apparently non-silver cat has been documented several times. For example, Neils C Pedersen, Feline Husbandry, 1991 (pg 67) reported “several cases on record of black cats breeding as smokes.” Robinson’s Genetics for cat Breeders and Veterinarians, 4th Edition, 1999 (pg 142) reported “occasional cats with no visible white undercoats that nonetheless breed as smokes.” Gloria Stephens’ Legacy of the Cat, 1989 & 1999 admitted “we do not understand about silver or the gene(s) that cause a solid-colored cat to be smoked.” The variability of smoke cats, ranging from poor smokes and hidden smokes to light smokes, is mentioned as far back as Frances Simpson in the early 1900s (this book pre-dates modern inheritance genetics so you have to rely on descriptions, some of her light smokes are evidently smokes). Some apparently solid cats are genetically smoke, but other genes prevent the pale undercoat showing up. However, could there be another form of silver, one that is either hypostatic (masked fully or partially by other colour genes) or is a second recessive allele of the inhibitor gene I and is recessive to both I (silver) and i (golden), but which produces a form of silver, perhaps i2 where dominance is I > i > i2.
All non-silver cats are, by default, by golden, though the golden will not show up in solid (non-agouti) cats. However, unexpected silver cats has turned up from time to time when two non-silver cats (by default golden) have produced silver offspring or a non-silver (golden) mated to a heterozygous silver (silver carrying golden) have consistently produced silver kittens, but non goldens even though the law of averages would expect half of the offspring to be non-silver.
What are the possibilities?
- Mutation of the gene into the dominant inhibitor (silver) is plausible if it happened in the germ cells (ova, sperm) of just one cat. Germ-line mutations sometimes happen.
- The supposedly golden cat (which should be homozygous for the golden form) might be a very tarnished silver due to other genes it inherited alongside the dominant inhibitor (silver) gene.
- There might be a second recessive form at the I locus, one that is recessive to both I (silver) and i (golden), but which produces a form of silver. In a breed where silver is not permitted, the occurrence of unexpected silvers might be due to a 3rd allele that is recessive to golden.
- A hypostatic gene for silver that manifests only when epistatic (masking) genes are eliminated. An epistatic gene is “dominant” over genes on other chromosomes (an example is “dominant white” masking other colours). Likewise a hypostatic gene is “recessive” to genes on other chromosomes. (I use the terms dominant and recessive outside of their strict meaning here)
- 2 separately inherited gene pairs (different loci) interact to produce the visual effect of silver. When inherited separately there may be no visual effect or a different effect e.g. lightening of the coat colour (“powder coat”).
In North America there is a phenomenon in some breeds called “powder coat” and “high colour.” A powder coat means a lighter colour cat while high colour indicates a darker colour. This reflects variations in depth of colour. It is seen in solid colours such as cream, lilac and blue, but descriptions of variations in tone have been mentioned by Soderbergh (1950s) and Frances Simpson (early 1900s), especially in blues and the variations are generally attributed to polygenes. The inheritance of powder coats is predictable. In some Burmilla and Burmese lines, powder coats have been linked to unexpected silver offspring (mismating was ruled out) leading some to wonder if the powder coat and a hypostatic silver are linked.
Whatever the actual genetics turn out to be – and whether there is a single Wide Band gene of a handful of polygenes – the Silver and Golden series are attractive cats in both longhair and shorthair varieties.
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