How is iris heterochromia reflected?

Many species have the probability of abnormal iris color, but this phenomenon appears slightly more frequently in cats. Today, we will talk about the secrets of different colors of iris hidden behind the mysterious and lovely big eyes of cats.

Cat iris heterochromia? Heterochromatic iris, also called heterochromatic pupil hole, has two kinds, one is heterochromatic iris, which is what we call Yuanyang eye, and the other is that one eye has two colors, which is called monocular heterochromatic iris. ?

Figure 5? A cat with different eyes?

Figure 6? Monocular cat?

Because cats with white hair and blue eyes are very popular, people cross-breed mandarin ducks with yellow-eyed white cats and blue-eyed white cats. Cats with Yuanyang eyes are all heterozygotes, which not only make up for deafness in both ears, but also keep beautiful blue eyes. ?

What determines the color of cat iris? ?

Figure 1? Heterochromatic phenomenon of cat iris (picture from network)?

As we know, cats' eyes are similar to human beings, and there are many different colors: blue, brown, green, brown and so on. Most cats are the same color, but in white strains or strains dominated by white, the colors of the two eyes will be different. To find out why this phenomenon occurs, we must first understand the structure of the cat's eye and what determines its color. ?

Figure 2? The structure of the cat's eye (picture from the Internet)?

The basic structure of cat's eye is similar to that of human eye, and it is also composed of cornea, iris, conjunctiva, retina and other structures that are mainly responsible for imaging. The color of cat's eye is mainly determined by the pigment contained in iris. ?

Kittens will open their eyes at 5- 14 days, when the iris appears gray-blue, which is the so-called gray-blue eyes. Then in the next few weeks, the color of the iris of the eye will gradually change with the appearance of melanocytes, and the color of the iris will stabilize at 7- 12 weeks or even longer, and gradually become the color of the iris of a cat. There is a circular opening in the center of the iris, which is the pupil. Pupils can change their size and shape according to the light intensity in the environment. ?

Cat's iris is divided into two layers, the outer layer is matrix, the cells are loosely arranged, and the inner layer is epithelial tissue, and the cells are closely arranged. Both layers contain pigment-producing cells, and the color of iris is determined by the number and activity of these cells. ?

If there are no pigment cells, the cat's eye looks blue; If the number of pigment cells is small, the cat's eye is green; If there are many pigment cells, the cat's eye will be yellow and brown. ?

In addition, the transparent structural lens in the cat's eye can reflect external light like a piece of glass. Similar to the phenomenon encountered when observing the color of glass, from the front, glass has no color, but if you move the angle a little, you will see it is green or blue. ?

Similarly, the transparent structure in the cat's eyes will show a certain color because of the reflected light. So more strictly speaking, the color of cat eyes is determined by this light reflection and the color of iris. ?

It is worth noting that wild cats' eyes are usually brown, and only domestic cats' eyes will show a variety of colors, including blue, green, yellow, orange and brown, and each color has a tone change from light to dark. The transition of these colors is not intermittent, but continuous. ?

For example, the colors between blue and green may appear as ocean green and light green, and lemon and dark orange may appear between green and yellow. ?

Figure 3? Range change of cat iris color

Is the blue-eyed white cat just a coincidence? ? Cats with blue eyes are loved by people because of their beautiful appearance. Moreover, we will also find that blue eyes usually appear on white cats. Is it just a coincidence? ?

Figure 4? A white cat with blue eyes

In fact, the color of the cat's eye iris is closely related to the coat color. The white dominant gene controlling coat color prevents melanin from reaching the iris during the cat's growth period. The iris appears blue because there are no pigment cells, which is why white cats are more likely to have blue eyes. ?

In addition, some kinds of cats are more likely to have heterochromatic pupil holes and blue eyes, such as Brahma in Turkey, angola cat in Turkey, oriental shorthair, Japanese short-tailed cats, Persian cats or Royal Thai cats. These cats have blue eyes not because of the white dominant gene that controls coat color, but because of the white spot gene they carry. ?

Japanese bobtail cat (picture from the Internet)?

Heterochromatic pupil ≠ Little deaf? Friends who have owned cats must have heard the saying: "A cat with lonely eyes is deaf." . This has to make people feel: what a jealous cat. With its white coat color and unique beautiful eyes, it is so cute and cute, how can it make people deaf! ?

It is scientific that cats with ectopic iris are prone to deafness. The source of hearing loss is not so much because of eyes, but because of coat color. This is because the genes that control the development of cat cochlea are closely related to the genes of coat color and iris color. The gene responsible for white fur is closely related to the gene responsible for blue eyes, and the gene responsible for hearing is directly related to these two genes. ?

White cats with blue eyes can easily hinder the internal development of cochlea, so white cats with blue eyes have a 60% to 70% probability of deafness, while white cats with different irises have a high probability of being born deaf on one side of blue eyes. ?

As we mentioned earlier, there are two possible reasons for the blue eyes of cats. One is that the white dominant gene causes the disorder of iris melanin precipitation. In this case, the blue eye side of the white cat crossing with other cats is likely to be deaf. ?

In addition, there is another kind of blue eyes caused by white spot gene, which generally appears in non-pure white cats. If a kitten born by crossing with other cats has blue eyes, such as Siamese cats, it will generally not affect the cat's hearing. ?

Figure 7? A blue Russian cat with only one pair of eyes?

Although congenital deafness is a big shortcoming, cats in congenital deafness can grow, develop and live healthily. This is because they perceive external sounds not through their ears, but through the meat pads under their paws. There are quite a few tactile receptors in the meat pad, which can sense the tiny vibration of the ground. Cats use it to find out whether there is anything in the underground mouse hole and whether something needs to be done. ?

Only cats have "lover's eyes"? In fact, not only cats, but also the characteristics of Yuanyang eyes will appear in other species. For example, MIMI, the dog of Hong Kong artist Lin Ruimeng, is a sled dog with mandarin duck eyes. In addition, pigeons also have lovers' eyes. ?

Figure 8 Husky with lonely eyes (picture from the Internet)?

Not only dogs and birds, but also a few people in our ethnic group will have mandarin duck eyes. For example, Sarah McDaniel, a very popular cat-eye supermodel recently, is widely known for her natural colored pupils. Her left eye is blue, her right eye is yellow and her two big eyes are clear and bright. At the same time, she is a little more mysterious and sexy. ? ?