Ojos Azules
Encyclopedia
Origin
Cats with dark blue eyes were discovered in New MexicoNew Mexico
New Mexico is a state located in the southwest and western regions of the United States. New Mexico is also usually considered one of the Mountain States. With a population density of 16 per square mile, New Mexico is the sixth-most sparsely inhabited U.S...
among feral cat populations. The first cat, discovered in 1984, was a tortoiseshell
Tortoiseshell cat
Tortoiseshell describes a coat coloring found mostly in female cats. Cats of this color are mottled, with patches of orange or cream and chocolate, black or blue. They are sometimes called torties...
named Cornflower. She was bred to males without the trait, which proved to be dominant, as all her kittens showed it. The breed was founded and named Ojos Azules, Spanish
Spanish language
Spanish , also known as Castilian , is a Romance language in the Ibero-Romance group that evolved from several languages and dialects in central-northern Iberia around the 9th century and gradually spread with the expansion of the Kingdom of Castile into central and southern Iberia during the...
meaning 'Blue Eyes'.
Genes
Ojos Azules are remarkable for their deep blue eyes. Unlike the blue eyes seen linked to the genes in bicolor catBicolor cat
A bicolor cat has white fur combined with fur of some other color, for example black or tabby. There are various patterns of bicolor cat. These range from Van pattern through to solid color with a throat locket...
s and cats with point coloration
Point (coat color)
Point coloration refers to animal coat coloration with a pale body and relatively darker extremities, i.e. the face, ears, feet, tail, and scrotum...
, both of which suppress pigmentation, this gene is not linked to any certain fur color or pattern, giving the opportunity to have cats with dark coats and blue eyes. The depth of color in the eyes is greater even than that seen in a Siamese (cat)
Siamese (cat)
The Siamese is one of the first distinctly recognized breeds of Oriental cat. The origins of the breed are unknown, but it is believed to be from Thailand. In Thailand, where they are one of several native breeds, they are called Wichian Mat...
, and does not cause squinting, deafness or cross-eye. One indicator of the Ojos gene is a flattened tail-tip. Following genetic investigation by Solveig Pflueger, breeding resumed in a small way with attempts to breed Ojos Azules without the lethal genetic defects. It was discovered that when the gene is homozygous it causes cranial deformities, white fur, a small curled tail, and stillbirth. However, when the gene is heterozygous, those lethal genetic mutations do not manifest. The result is that breeders must cross the blue-eyed cats with non-blue-eyed cats, assuring a litter of about 50/50 blue/non-blue-eyed kittens. Though only half of the kittens are then part of the Ojos Azules breed, this avoids having much of the litter comprise deformed dead kittens.
Although the eye color is described as having depth "even greater even than that seen in a Siamese (cat)" it, in fact, does not. The blue color seen in cats is due to the same physical phenomenon, the absence of melanin in the iris. The cause of the absence of pigment differs between Siamese, white cats, and Ojos but the end result is pigment loss and blue eyes. The depth of color of the blue eyes is due to currently unknown polygenetic variations. The depth of eye color can be selected for in breeding programs and current show Siamese have extremely deep eye color.