Golden tabby
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[Photo] Golden tiger at the Buffalo Zoo. Date 16 December 2006. Author Dave Pape (http://commons.wikimedia.org/wiki/User:Davepape). Released into the public domain by its author.
The golden tabby tiger or golden tiger is an extremely rare colour variation caused by a recessive gene and now found only in captive tigers. Like the white tiger it is a colour form and not a separate species. It is sometimes referred to as the strawberry tiger due to the strawberry blonde coloration. No official name has been designated for the color.
The golden tabby's white coat and gold patches make it stand out from the norm. Their striping is much paler than usual and may fade into spots or large prominent patches. Golden tabby tigers also tend to be larger and, due to the effect of the gene on the hair shaft, have softer fur than their orange relatives.
As is the case with white tigers, the unusual golden color is caused by a recessive gene; in the case of the golden tabby this is the wide band gene while the white tiger is due to the color inhibitor (chinchilla) gene. There are currently believed to be less than 30 of these rare tigers in the world, but many more carriers of the gene.
Like their white cousins all golden tabby tigers have mainly Bengal parentage, but are genetically polluted with the genes of the Amur tiger via a part-Amur white tiger called Tony who is a common ancestor of almost all white tigers in North America. The suggestion that this coloration is caused through the deliberate breeding of Amur tigers with Bengal tigers is a popular myth founded on this fact. All golden tabbies appear traceable to one of Tony's male descendents, Bhim.
The golden tabby in the wild
India has records of wild golden tigers which date back as far as the early 1900s. There have been suggestions that the tendency for this coloration gradually developed in a small group of tigers living in an area of heavy clay concentration. The unusual color would provide these tigers with extra camouflage. The theory remains unproven, however, inbreeding of a small isolated group of tigers could cause the recessive golden tabby gene to emerge if at least one of those tigers carried the recessive gene for the golden color and bred with its own offspring (as has happened in captivity).
Golden tigers and stripeless or nearly stripeless tigers may occur in the same litter. This is due to the effect of the wide band gene on the normal orange colour and the white colour respectively. The wide band mutation is not found solely in white tigers and may also be carried by normal coloured tigers, however carriers of the wide band gene are probably no longer found in the wild. Wild-born golden tabby tigers might be disadvantaged as they are less well camouflaged than normal orange tigers. The last known Golden Tabby tigers were shot outside of Mysore Padesh, India in the early 20th century.
Golden tabby tigers in zoos
Few zoos have bred or exhibited golden tabby tigers and many have no knowledge of the color or its mode of inheritance. It therefore usually appears by accident when breeding orange and white tigers together rather than through planning. As white tigers and heterozygous normal coloured tigers are traded and loaned between zoos and circuses for breeding, if they also carry the wide band gene that gene becomes widespread. When their descendents are mated together, the golden tabby colour shows up if both parents are gene carriers and pass it on to their offspring. Unless golden tabby cubs are born, the zoos may have no idea that the parents carry that gene. If the parents have golden tabby parents or siblings, zoos can hazard a guess that their tigers carry the gene.
The first golden tiger cub born in captivity was in 1983 and this came from standard-colored Bengal tigers, both of whom carried the recessive genes for both the golden tabby and white colours. It was born at The Institute of Greatly Endangered and Rare Species in Myrtle Beach, South Carolina.
An example of a Golden Tabby is in at Dream World in Australia. Samara, a normal orange tigress, had been mated with nearly-stripeless white male, Mohan. Her litter included one normal orange cub (Sultan), the first white tiger born in Australia (Taj, also nearly stripeless) and the first two tabby-colored tigers (male Rama and female Sita) born in Australia. The cubs weighed around 1.5 kilograms and measured approximately 30 centimeters in length. They were removed from their mother soon after birth and hand raised. The births and hand-raising process were filmed and presented in an hour long documentary. Golden tabby Sita will be mated to an unrelated normal orange tiger called Kato.
Diamond, a male golden tiger, is housed at the Isle of Wight zoo in the UK. Because he is inseparable from his normal coloured sister who also carries the golden gene, Diamond was castrated to prevent inbreeding. Longleat Safari Park in the UK also has a golden tiger. Glasgow Zoo's golden tiger, Butu (also spelled Bhutto), obtained from Longleat, went to Germany when Glasgow Zoo closed. Longleat previously had an elderly golden tiger named Sonar, but he passed away in 2006.
Though golden tabby tigers are not deliberately bred for by conservation-minded zoos they have joined the white tiger in becoming popular for use in stage shows and similar events. A few private breeders are attempting to produce golden tabby tigers alongside white tigers to meet demand. The golden tabby tiger and the white tiger could therefore be regarded as human-perpetuated "breeds", however, some zoos and wildlife parks refer to both golden tigers and white tigers as endangered.
Golden Tabby Tiger Genetics
Births like Dreamworld's where the cubs are of differing colors are not unusual because the white and golden tabby colours are caused by combinations of hidden recessive genes carried by the parents. White tigers, such as Dreamworld's Mohan (named after the white tiger captured in India in the 1950s), are highly inbred. Inbreeding reduces genetic variability and may cause hidden genes to manifest as there is a greater probability that two recessive genes will meet up.
Analysis of golden tabby tiger family trees shows that golden tabbies are genetically normal orange coloured tigers with the addition of a recessive modifiying gene, probably the wide band gene. This same wide band gene also gives rise to stripeless white tigers. A white tiger that inherits two copies of the recessive wide band gene will be a stripeless white. A normal orange tiger that inherits two copies of the recessive wide band gene will be a golden tabby. The wide band gene is carried independently of the white gene.
All golden tabby tigers seem traceable to a white tiger called Bhim, a white son of Tony. Bhim was a carrier of the wide band gene and transmitted this to some of his offspring. Bhim was bred to his sister Sumita (also a carrier of the wide band gene), giving rise to stripeless white tigers (i.e. having two copies of the wide band gene). Bhim was also bred to a normal orange tigress called Kimanthi and then to his own orange daughter Indira from that mating. The mating of Bhim and Indira resulted in striped white, stripeless white, normal orange and golden tabby offspring indicating that both Bhim and his daughter carried the wide band gene. When the golden tabby male offspring was mated to the normal orange female offspring, both golden tabby tigers and white tigers resulted.
At Dreamworld, Australia, it was demonstrated that the mating of a nearly stripeless white tiger to an orange tigress that carried both white and wide band genes would result in golden tabby offspring alongside nearly stripeless white and normal orange cubs.
http://en.wikipedia.org/wiki/Golden_tabby
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