BLUE-EYED BREEDS / DOMINANT BLUE EYE (DBE) - PART 2
Blue-Eyed Breeds 1 - Altai, Topaz, Barnaul, American Ojos Azules, Breeds derived from Altai & Topaz
Blue-Eyed Breeds 2 (this page) - Spontaneous Blue-eye Mutations in Mink Ragdolls, Australian cats, Chinese cats, Silver & Golden British Shorthairs, Historical Reports.
Reviewing the Dominant Blue Eye Gene in the Ermine Trace Cattery (Elizabeth Lipovenko)
BLUE-EYED RAGDOLL (SPONTANEOUS DOMINANT BLUE EYE MUTATION)
In 2020, Helen Fitton reported an odd-eyed Ragdoll named Jean Genie. A second odd-eyed Ragdoll kitten, a blue smoke mink mitted, was born and his father was the seal smoke half brother (same mother) to the father of Jean Genie. The eyes were distinctly different shades, with one being blue because of the colourpoint gene, but the other being blue due to the white spotting gene. Helen initially wondered if there was any link to the silver (inhibitor) gene because of the blue-eyed silver series cats that had been reported elsewhere.
The mother of Jean Genie (aka Eva), the first odd-eyed kitten, was a blue smoke mink bicolour and the father was chocolate smoke colourpoint mitted. The father of the more recent kitten was high grade seal smoke mink mitted, and the mother was blue smoke colourpoint mitted.
Most people's first comment is that Niamey, a seal mink Ragdoll has blue eyes and not aqua eyes. While aqua (midway between a colourpoint's blue-eyes and a sepia's golden-eyes) is the preferred colour in mink pattern cats, it's not the only colour possible. Eye colour in cats isn't as simple as mixing paint. Mink pattern cats have a range of eyes colours from blue through to yellow, but breeders prefer aqua.
At first, the odd eyes and intense blue eyes turned up in mink Ragdolls that were smoke or had a smoke parent. By October 2021, there were more odd eyed cats and some beautiful intensely blue eyed mink bicolour boys. An odd-eyed blue sepia bicolour sired a litter of sepia kittens; a blue sepia (without white) had blue eyes but the rest of the litter had aqua eyes. A blue mink in the litter had a very short tail and white toes on one back foot.
In the 18 months up to October 2021, a further 7 odd eyed Ragdolls had been born. Not all had a smoke parent, but all traced to Niamey, the blue-eyed seal mink Ragdoll. Vet Sarah May believed that Helen's mink Ragdolls had a spontaneous mutation for Dominant Blue Eyes (DBE). The family tree shows the descendants of Niamey, Helen's foundation mink female with colour coding showing the cats with odd eyes or intense blue eyes (DBE).
Dominant blue eyes have turned up in other breeder's Ragdolls though I don't have details for linechasing back for common ancestors. Some breeders have been accused of having experimental lines or crossing their Ragdolls to Altai or to experimental blue-eyed British Shorthair/British Longhair cats, or of deliberately breeding odd-eyed and blue-eyed mink cats so they could charge more for the kittens.
It seems likely that some forms of dominant blue eyes (actually an incomplete dominant) have been hiding in plain sight, probably in bicolour and solid white cats which naturally have blue eyes. It then gets noticed when intense blue or odd eyes appear in cats with little or no white. It is also possible that the gene involved is prone to mutation for some reason.
AUSTRALIAN DOMINANT BLUE-EYE MUTATION
David Karamatic is working with a dominant blue eyed mutation discovered in tropical north Queensland, Australia. He was notified of some "free to good home" kittens that had retained their blue eyes. There were four in the litter three with blue eyes and one odd eyed. At first he thought it was the influence of white-spotting, but the odd eyed kitten was nearly completely black. He obtained the last kitten available, and at seven months old its eye colour is very deep and vivid almost violet. It would be interesting to see if this gene is the same as the Celestial / Topaz or perhaps on the same locus. David first wants to find out if the mutation is the same as his imported French Celestial (Maidee, from Chatterie d'Aerlin), and he is also submitting samples for DNA tests.
BLUE-EYED SILVER AND GOLDEN BRITISH SHORTHAIRS
Two golden British Shorthairs with blue eyes - Ermine Trace Athens and Ermine Trace Zarafina) both trace their ancestry via Ermine Trace Nadeya to a very blue-eyed chinchilla point male, Shoenwig Teodoro and his mother Schoenwig Mona Lisa, also a very blue-eyed chinchilla point cat. Mona Lisa's mother is Passimilla's Upper Class, also a very blue-eyed chinchilla point cat. It is possible that in selecting for very blue eyes, a gene mutation may have been overlooked. Because pointed cats have blue eyes, it is also possible the mutation could have been hiding in plain sight.
Information on another dominant blue-eyed mutation, with no apparent links to the Ermine Trace cats, has been researched and provided by Sarah May. It occurred in the Nanotigr cattery. When the breeder gave up breeding, the blue-eyed cats went to Angela Savenko (Hermes Cattery), a breeder of bicolours, and were also bred to Selkirk Rex. She sold a blue-eyed black-tipped British Shorthair to British SH/Selkirk Rex Cattery annealtindan (Kaan Altindan) in Turkey. It isn't known whether the Capuchino line descended from Roddiffer have produced any cats with odd eyes. The breeder believed them to be "latents" (having the blue-eyed mutation, but not displaying it), but they had no white lockets which are normally indicators of the mutation.
BLUE-EYED BURMILLAS, BURMESE AND TONKINESE
Blue eyed kittens sometimes occur in Burmilla (derived from Burmese x Chinchilla ancestors) lines with browns and chocolates in the pedigree. Although they don't match the breed standard (green eyes), they were usually the first kittens to be sold. The blue eyes likely trace to a Himalayan ancestor many generations ago. DNA tests have identified the colourpoint (Siamese) gene in some Burmillas. In the 1980s, Himalayans/Colourpoint Persians and Chinchillas were crossed to produce the lynx and smoke point series Himalayans/Colourpoint Persians. Genetically chocolate cats (and chocolate carriers) were used in the breeding programmes and some Chocolate Chinchillas/Goldens were registered without stating they were chocolate. Aquamarine eyes have also been seen in Burmillas, where the Burmese sepia gene meets up with the colourpoint gene. Because many breeders breed for light coat colour without markings, aquamarine eyes (linked to mink colour) are less important than clear silver. This also means that Burmillas have become lighter in colour than the original British cats. DNA testing on some Burmilla lines also identified the white gloving gene is present although it is not visibly expressed.
There is a line of blue-eyed Tonkinese from Joan Bernstein who bred some blue eyed sepia variants. Descendants of her cats continue to produce blue eyed sepias and blue-eyed minks.
CHENGGE MAO CATS, CHINESE DOMINANT BLUE-EYE MUTATIONS
In November 2020, Rano Makarenko sent me information about some Chinese cats known as Chengge mao. The variety lives in Chengge and the breeder selects them for mouse-catching and is not at all interested in genetics questions. Originally, the Chengge mao was white with a coloured tail, symbolic of good mood and richness because of a resemblance to a rice bowl with chopsticks (Van pattern without head markings). Then the cats started producing blue eyed cats from the white cats with coloured tails.
Blue-eyed solid colour cats (often red-colour cats) are known to be bred and sold in part of China, but there is no control over the breeding and the gene(s) involved are unidentified. One breeder reported a hgh mortality rate with 50% of kittens from his blue-eyed red ticked female mated to a blue-eyed red classic tabby male being solid white and stillborn/dying at birth. Though there could be various reasons for this, there is a possibility of 2 incompatible blue-eye genes being bred together. Breeding the blue-eyed red-ticked female to an unrelated normal-eyed cat and then breeding a male offspring back to the red-ticked female would produce kittens with only one blue eyed mutation (and could also show if the stillbirths were due to a reproductive issue with the female herself.)
OTHER BLUE-EYED CATS & HISTORICAL REPORTS
The blue-eyed trait turns up surprisingly often in random-breeding cats. A grey bicolour (tuxedo pattern) cat with intense sapphire blue eyes was found on a country road in Windellama, New South Wales, Australia by A M Schnieder. Since the Ojos Azules has not been imported into Australia, this represents a spontaneous mutation among the feral population. Whether it is the same as the American Ojos Azules mutation is not known.
Below: silver tabby female feral cat, black-and-white male, red tabby (with white bib) male, red tabby longhair male, odd-eyed tortie, black-and-white male.
Wain Harding, Secretary Egyptian Mau Breeders & Fanciers Association (May 1971 Cats Magazine): "I was very interested in your recent article ‘The Cat That Couldn't Be Bred' by Mrs. Sayer. The Egyptian Mau breeders have recently had four blue-eyed kittens from different parents. These kittens are beautiful well spotted, silver Mau with deep blue eyes. All of these kittens share a common grand or great-grand parent (Kattiwyckes Gulliver x Kattiwyckes Trinket owned by Mrs. Ann Cahill). The first of these blue-eyed beauties appeared in one of my own litters (Kattiwyckes Umm Usada bred to her son Bast's Zosser). I kept waiting for this kittens eyes to change as it is often four months before a Mau kitten's eyes change from blue to the desired gold. I exhibited Chui Chali at the Fall Baltimore CFA show when he was six months old. I still insisted that his eyes would change to the admiring public. The kitten's eyes never changed and he grew up and sired a litter now nine days old. We are anxiously waiting for the kittens to mature.
The second kitten appeared in a litter of Ann Cahill's breeding. This beautiful young female, Kattiwyckes Dynamite, will soon be bred to Bast's Chui in the hopes of producing an all blue-eyed litter. The third blue-eyed baby appeared in a litter of kittens bred by Barbara Abruzzo of New Jersey. The fourth kitten appeared in a litter bred by Joan Dewberry of Ta-Mera Cattery in California. We are very proud of our blue-eyed stock and have great expectations for these kittens. The most plausible explanation for the blue-eyed mutation has to do with the amount of inbreeding that has been necessary to keep the Egyptian Mau the pure, natural breed it was upon importation. Bast Chui Chali is now at stud to Egyptian Mau queens of pure ancestry as well as to approved Foreign Short- hair breeders interested in breeding a foreign type cat with blue eyes. We are helping a breeder develop blue-eyed blacks at the present time. The Egyptian Mau Breeders and Fanciers Association are happy to announce blue eyed Mau kittens and gene-carriers in the near future."
In Cats Magazine. October 1972, Mrs. Dagmar Thies, from W. Germany wrote: "From an American cat-breeder, I recently heard that it would be possible to breed blue-eyed Black Foreign Shorthairs. We are breeding these wonderfully charming cats, Calling them "Ebonies." After three generations of back-crossing self-coloureds to best typed Siamese we started mating Black to Black, and now we have the third generation of Ebonies. Two of our queens, one second and one third generation self-bred, are showing very light blue-green eye colour, without any yellowish glimmer. Would it be possible to reach blue-eyed kittens by back-crossing them to Siamese once more? Do you think that blue eyed Blacks would be worth breeding?"
Don Shaw (Cats Magazine's resident geneticist) answered: "Your letter is most informative. The enclosed photographs were excellent. You have truly obtained, the Foreign Shorthair type in your Ebonies. In answer to your question; there is no genetic evidence to my knowledge which would suggest that the genic factors for blue-eyedness in self-colored cats can be obtained by crosses with Siamese. All the data thus far examined by us, indicate that the basic causative genic factor for blue eyedness in Siamese is intrinsic to the "cs" allele which is responsible for the temperature sensitivity color-point affect. If this is indeed the case, then this genic factor must be eliminated if you hope to obtain true breeding self-colored cats. From the information at hand, it is very likely that the two queens you described may have picked up eye color factors from the self-colored cats in their background which may or may not be being amplified by the "cs" allele, which could still be heterozygous in these particular, cats. No, I do not think that crosses with Siamese would either help you toward blue-eyed black nor would it help you toward your goal of true breeding Ebonies. Are blue-eyed Blacks worth breeding? Yes, from a genetic point of view they would provide us with entirely new concepts concerning eye color. Over the years I have heard reports of truly blue-eyed Blacks, but in my ten years of searching I have not come up with one valid case. Somehow, people say they have had them or have seen them, but when I go to examine the cat it is not there, or the eyes are green. They may be bluish-green, but nonetheless they are green, not truly blue as we get in Siamese and Blue-Eyed Whites. From a sales view point, I can assure you there would be a market in this country and I strongly suspect the market would be world-wide."
In Cats Magazine July 1973, Elaine Brenna wrote: I read with interest your remarks in the March [issue] about the rarity of blue-eyed black cats. I am not a breeder of cats although I have two, and a picture of one is enclosed. As you can see Tosca's eyes are quite blue; there is no camera distortion here. He is also black, but not quite jet black. This picture was taken when he was about four months old; he's now six months old and has matured quite a bit. He has not been altered. His eye color is still the same and his coat has taken on a glossy, sleek appearance. He resembles a Burmese quite strongly except for his eye and coat color. Tosca is quite intelligent and makes a wide variety of sounds. He does have one white patch on his lower abdomen. Whether your article was referring to Blue-Eyed Persians that are black or just blue-eyed black cats in general I don't know. I thought I'd send this on to you for information purposes only. Tosca's origin is unknown."
Don Shaw (Cats Magazine's resident geneticist) answered: We greatly appreciated the information and picture of the "blue-eyed black." Unfortunately, we cannot reproduce the picture, but according to the photograph, Tosca does indeed have blue-eyes. In fact, they are a fantastic blue. If, as you say, there is no camera distortion, they might be called royal blue - it is virtually unbelievable! The closest thing to this eye color I have ever seen is a deep violet blue which can be traced back to a particular Siamese line. A similar deep blue is relatively common in very young kittens right after they open their eyes, but this generally changes by four months and certainly by six months. If they are still this fantastic blue at eight months, we at CATS would seriously consider publishing a color photograph if you could obtain a good sharp color transparency with neutral background. That blue-eye coloring would be overwhelming on a cat of any color. >Now to the genetics — you state that there is "one white patch on his lower abdomen: "This would indicate that he is carrying the pied, white-spotting S-allele. Am I seeing things, or is, it camera distortion, or is there really a tiny cluster of white hair at the inner edge of the left eye near the bridge of the nose? Also please examine his toe nails—are they all showing darkish marrow? If this blue-eye coloring remains, you may well have an excellent example of the S-allele's producing blue-eye with very little indication of its manifestation in producing white-spotting."
CONSIDERATIONS FOR ALL BLUE-EYED BREEDS
There are various known and unknown genes involved in white spotting and in blue-eyes. In solid white and high white cats there is a link to deafness because melanin is involved in the development of the inner ear (the part that detects sound vibrations). BAER testing (acoustically evoked brain stem responses) is used by many European breeders to ensure that they don't deliberately breed deaf cats. The prevalence of deafness and partial hearing in an experimental colony of white cats was 67% (deaf - 0.55 coefficient of heritability) and 29% (partial hearing - 0.75 coefficient of heritability) which suggests a pleiotropic major gene (a gene that has 2 seemingly unrelated traits) and the likelihood of polygenes.
Geigy CA, Heid S, Steffen F, Danielson K, Jaggy A, Gaillard C (2007). "Does a pleiotropic gene explain deafness and blue irises in white cats?". Veterinary Journal. 173 (3): 548–553. PMID 16956778.
This was commented upon by Strain GM, in "Deafness in blue-eyed white cats: the uphill road to solving polygenic disorders."Vet J. 2007 May;173(3):471-2. Epub 2007 Feb 21.
In some species, such as ferrets and "splashed white" horses, certain white spotting patterns are linked to mild forms of Waardenburg syndrome (syndrome means "collection of traits consistently occurring together"). Though suspected by some owners, this has not been confirmed in white-marked cats. Mutations in several different genes can cause similar visual appearance. The traits occurring together include a specific distribution of white, premature greying, brilliant blue eye-colour in one or both eyes, or eyes where the iris has two different colours (sectoral heterochromia), congenital deafness, broader nose and shortened tail. Apart from deafness, which is not unusual in blue-eyed white cats, the traits are cosmetic and have less impact than (for example) skeletal problems in Scottish Folds or spinal problems in Manx, which are both managed by careful selective breeding.