RUSSIAN SUNSHINE - GOLDEN COLOURS IN SIBERIAN AND KURILIAN BOBTAIL CATS
This page results from a discussion on the inheritance of black tail-tips in some red/red-tabby Kurilian Bobtails. The first issue I noted was that the cats' colours were registered as golden shaded/golden tabby when a visual inspection shows them to be torties or reds. In addition, the cats bred as torties and reds!
In 2014, Anna Hakkarainen wrote to me about some curiously coloured Russian-bred kurilian Bobtails. Some Russian breeders have kurilians that display amber-like colors (the late black-to-red colour change seen in Norwegian Forest Cats). Anna had encountered Kurilian kittens that were born reddish with a black tail-tip. This occurred when both parents were registered as "golden" (e.g. golden shaded, golden tabby) which many in the cat fancy understood to be related to the silver inhibitor. It's a misconception that golden cats have to have silver ancestry. If cats inherit the wide-band trait independently of the inhibitor this produces the golden colour.
At first we wondered if it was some type of birthmark, but it was curious that several cats had black-tipped tails. Then we wondered if the dark shading was somehow restricted to the tail-tip, with a black-to-red colour-change occurring before the kittens were born. We knew that greyish pigment can occur on red cats on the tail, face and feet, perhaps due to temperature. Looking at the pedigrees as well as photos of the cats, there appeared to be discrepancies between the phenotypic (visually expressed) colours and the registered colour. The appearance of red/red-tabby cats that followed the rules of inheritance for the sex-linked red gene, but whose parents were allegedly golden shaded/golden tabby cast doubt on the registered colours of parents and grandparents.
At first we put aside the black tail-tip as a curiosity, but this might actually be a diagnostic feature of an extreme form of wide-banding (golden) where a black shaded/tipped/tabby cat appears to be red apart from the tail tip and paw pads. Because of breeder sensitivities, I can't use photos of the actual cats whose pedigrees don't reflect their actual colours.
WHERE DID THE REDS COME FROM?
Below is the pedigree of a visually red-and-white cat that is registered as “black golden shaded.” At first glance, the problem seems to come from the mother's side where a phenotypic spotted tabby-tortie has been registered as a black golden spotted tabby, but produces red kittens with black tail-tips. She also produces red-tabby-and-white female offspring which suggests that she has to be a tabby-tortie (and have the O gene for red colour) and not a golden tabby. We also found a shorthaired red-tabby-and-white male kurilian Bobtail (with a dark tail-tip) that was registered as a black golden blotched (classic) tabby with white. Show judges in Russia had voiced concern over such cats not being the colour it says on the pedigree papers. Recent research into extreme forms of wide banding suggests the judges are wrong and the pedigrees are correct after all!
Chart showing Pedigree vs Phenotype.
Mistakes can occur early on in a pedigree and propagate throughout later generations until it becomes impossible to explain away the indisputable red cats later on. That's when it's necessary to work backwards and re-evaluate the colours of the parents and grandparents. But in this case, wide banding explains the visually red cats and explains why they have black tail tips.
We also wondered if there was a terminology error regarding "golden" with the term being used to describe different things. The old school of thought is that golden cats must necessarily have silver ancestry. This is because early silver/chinchilla breeders concentrated on getting clear silver backgrounds and very light tipping. What they didn't know was that the silver colour came from one gene (the Inhibitor gene) while the clarity and reduction in tipping came from a separate gene (or set of genes) known as wide band. Wide band can be inherited independently of the Inhibitor gene, resulting in goldens. Golden cats need not have any silver cats in their ancestry at all.
This odd pedigree was resolved in 2017 with research into Golden Siberians and "Copper" British Shorthairs. "Copper" is an informal term denoting an extreme wide band effect on ticked tabbies where the black pigment is almost absent except on the tail-tip and paw pads. When patterned tabbies inherit the same degree of wide banding their markings are reddish rather than black, but they still have a black tail-tip and black paw pads.
Kurilian and Siberian breeders register their warm-toned black/brown tabby Siberian cats as "golden" to describe their brighter background colour dye to wide banding. This makes for problems if such a cat is transferred to a registry that understands golden to be related to silver and which doesn't recognise the wide band effect as a completely independent trait.
The Siberian is recognised in most colours and patterns, including colourpoints (Neva Masquerade), but not mink or Burmese colour restriction. The colours not recognised are chocolate/lilac, cinnamon/fawn, caramel/apricot in any pattern. Some registries recognise the "golden series" in Siberians. This is not recognised as "golden" by Britain's GCCF (a very conservative cat fancy). Siberian "Golden Tabby (with or without white)," Golden Tortie Tabby (with or without white)," "Golden Shaded" etc are not viewed as a genetic colour, but as a colour expression of Brown Tabby due to wide agouti banding on the hair shafts which limits the black banding and gives a warmer, brighter tone. This means that Siberian cats registered as "golden" by FIFE or TICA are re-registered as brown tabby (etc) when transferred into GCCF.
In Persians, Exotics and British Shorthairs, golden seems to result from with the wide band gene(s) and many of the cats have silver (dominant Inhibitor gene) somewhere in their ancestry because the wide band effect was selectively increased when breeding for very pale chinchillas. There is a misconception that when a cat with a silver parent isn't silver, it must be golden by default. Wide Band is independent from the Inhibitor gene; in golden cats, the dominant Inhibitor is absent, but wide band is present. Although "Wb" is treated as a single gene for simplicity, it appears to act as polygenes with an additive effect. In ticked tabby cats without silver, Wide Band restricts the pigment to the end of the hair leaving a pale golden band between the skin and the pigment. Through selective breeding, this effect has been maximised. The variability of the wide band suggests we should talk about Wb, Wb+ and Wb++ to describe cats with normal, intermediate and greater degrees of Wide Banding.
In 2013, Silvia Perego of Veselka Siberian Cattery in Italy described more such cats. Her stud male, Yankee Silviassib*PL, came from Poland and is a black silver tabby with white. When he arrived at her cattery at 4 months old, she noticed that he had a "strange" golden-brown spot on his neck and some little other spots on the back. At first this appeared to be rufism. His first litter included a silver tabby daughter, Veselka Lady, who had the same golden-brown spot on her neck. Another daughter, Veselka Lucy (from a bi-metal mother) also had a golden-brown spot on her neck. Another litter included a daughter, Lizzy, with the same spot. Then Veselka Lady, from the first litter, had her own litter with another silver-and-golden kitten like them. In summer 2013, Yankee had two kittens with the golden-brown patch. Although a judge suggested chimerism, the inheritance pattern indicated a newly emerging gene at work.
Research by Eleonora Ruggiero into the pedigrees of Siberian Cats brought out some intriguing details. For example in “Onix Gloria” lines there are golden tabby Siberians born of non-golden parents. In the pedigrees of “Siberian golden” (provisionally denoted sg), golden offspring are born from two non-golden parents. This means the gene was recessive and only expressed when two copies are inherited. It seems it is not the same as Persian golden (Wb with no inhibitor gene or with homozygous recessive inhibitor). Bimetallic females were often registered as tortoiseshell, but didn't breed as a tortoiseshell as they lacked the red (O) gene (evident when the paw-pads are examined and are never reddish). Their nose leather was dark pink, unlike the nose leather of tabby or genetic tortie cats. In the picture below, the cats have black tail-tips.
According to Irina Sadovnikova, Gelios (or Helios) Onix Gloria's rddish colour came from his mother, Bagriana Itamkhash. "Bagriana" means "scarlet."
The breeder that selected the "reddish" colour used a lot of inbreeding to fix the trait, confirming that it is recessive. The first "bi-metal" cats were probably hidden under the incorrect description of "silver cats with very high rufism."
When golden cats started turning up in silver Siberians, it resulted in cats expressing both colours in the coat; something impossible were it the same as Persian golden. The degree and intensity of golden colour (probably influenced by polygenes) rules out rufism or tarnish. These cats were initially referred to as “bi-metal” and later as "sunshine". Siberian sunshine was established in a breeding programme that used much inbreeding to bring out this recessive trait. Early sunshine cats were dismissed as silvers with high degrees of rufism and not bred from. In 2013, all known sunshine Siberians are agouti (tabby markings) and the colour hadn’t been seen in non-agouti (solid) cats. The sunshine gene affects the agouti (ticked) hairs only".
Sunshine silver looks very different from a silver with rufism; the nose leather is pinkish unlike that of a tabby cat. The red colour of a sunshine red tabbies and sunshine torties is brighter and the paws are lighter. The absence of pigment in the sunshine tabbies extends beyond the edges of the nose leather so they have no nose-liner and have whitish fur at the bottom of the nose. They are sometimes referred to as bimetallic because both silver and gold are present at the same time.
In Siberians, the Sunshine colour is inherited recessively. If you look at the pedigree of a Siberian Sunshine, it is apparent that sunshine cats can be born to two "non-sunshine," but when two sunshine cats are bred together they produce ONLY sunshine kittens. It brightens the agouti (ticked) areas of the coat. The colour seems to have arisen in a breeding programme in Russia Because the "golden" Siberians don't change from black/blue to a golden colour, it is also not an Amber or Russet mutation.
Suzanna Multhaupt has been looking into the golden colour and provided further information. The true black golden tabby Siberian is free of shading and free of silver influence. Characteristic honey-golden markings come in classic (blotched), mackerel and/or spotted tabby but the undercoat is golden in all cases with the tip of the hairs black (probably Wb). So depending on the season, the coat will appear darker or lighter. The kittens are born very dark. Distinguishing factors are jet-black paw-pads with long fur between the toes, black eye-liner and green eyes. The nose is pink and has no pigmentatation. Lips, too, are pink. The chin and chest are white but not solid colored. She has found it almost impossible to get a "pure" black golden from non-black-golden parents. As soon as you cross a black golden with any other color, be it agouti or non agouti, the golden undercoat disappears and you get interesting tabby offspring but no black-goldens. This is possibly where the bi-metallic (Siberian Golden + silver Inhibitor gene) or shading comes in.
Currently there are no reported Siberian cats that are sunshine non-agouti (aa) i.e non-tabby-patterned, only Siberian cats that are agouti (AA or A-). Non-agouti cats have nose leather that matches the marking colour e.g. black, blue. Because the Sunshine colouration appears darker at birth and gets clearer as the cats mature, this may be due to the extension gene, somewhat similar to the amber (ee) in the Norwegian Forest cats. It can occur in combination with colourpoint in the Neva Masquerade (colourpointed Siberian). It will take DNA studies to establish the actual mutation.
There needed to be a way of describing the brighter tone of some Siberian cats without using the word "golden". Siberian breeders asked for the term "Sunshine" to be recognised so that this gene could be discussed and traced in pedigrees without it being linked to cats with silver ancestry. Sunshine resembles Amber, but has important difference: sunshine kittens are born with black, not pink, pawpads which allows them to be distinguished from cats with the inhibitor gene.
We can have Brown/blue/tortie sunshine tabby for the cats without the inhibitor (silver) gene and Black/blue/tortie sunshine silver tabby or silver shaded for where the inhibitor (silver) gene is present. Thes can be in classic, mackerel and spotted varieties (ticked tabbies are not recognised in the Siberian), with or without white, or in silver shaded. The same colours are permitted in colourpoint patterns for the Neva Masquerade. The sunshine gene does not affect eye colour so this remains blue in the Neva Masquerade, preferable green in sunshne-silver cats and the normal eye colours for all other colours and patterns. A sunshine tabby without silver typically has pink nose leather without any dark line around it, and a very warm ground colour. Kittens are born with black, blue or tortie colours, but as they age these colours fade and can disappear resulting in warm apricot-reddish hairs with a tabby pattern and few dark hairs. The under parts are lighter. The paw pads match the base colour (black, blue, tortie etc), or are pink in cats with white paws. Sunshine silvers have both silver areas and sunshine areas.
Eleonora Ruggiero (All Breed WCF judge) presented an update on the genetic transmission of Siberian “Golden” (GoldenSib) and Siberian “Sunshine“ in 31 March 2018. It’s hard to continue the research while breeders register Sunshine cats as Goldens, and because cats born before 2017 were considered Golden at that time. The golden in the Persian cats shows "Wide banding" and is a "tipped" colour. The Golden in the Siberians is usually tabby. Sunshine and GoldenSib both appear to be recessive traits. A GoldenSib has nose leather the same colour as a normal tabby, but the base of coat is a warm hazelnut colour, not black or grey like a normal tabby. A “Sunshine” cat has pink nose leather and the base of the fur is apricot or light hazelnut. Sunshine carriers have warm hazelnut fur and the base of the fur is less grey or black than non-carriers of the gene. The Sunshine colouration looks darker at birth getting clearer afterwards, somewhat similar to the amber (ee) in the Norwegian Forest cats (which also produces pink nose leather). Sunshine cats do not have the amber or russet extension gene mutations. They might be due to another extension gene mutation, or to a different gene entirely. What is known for certain is that:-
Sunshine x sunshine produces only sunshine offspring.
GoldenSib x GoldenSib producse both Siberian Gold or Sunshine kittens.
Non-Sunshine/non-GoldenSib x non-Sunshine/non-GoldenSib produces non-Sunshine/non-GoldenSib kittens OR Sunshine kittens or GoldenSib kittens.
Sunshine x GoldenSib can produce Sunshine or GoldenSib kittens.
Sunshine x non-Sunshine/non-GoldenSib can produce non-Sushine/non GoldenSib, or Sunshine, or GoldenSib.
Eleanor hypothesises that the genes for GoldenSib and for Sunshine are two different alleles on the same locus. They are both recessive compared to non-GoldenSib/non-Sunshine. GoldenSib is dominant over Sunshine. The order of dominance appears to be: Non-GoldenSib/non-Sunshine >> GoldenSib >> Sunshine