Changing your Eye Color: Iris Color Facts

Color of the Iris

The iris is usually strongly pigmented, with colors ranging from brown to green, blue, gray, and hazel. Occasionally its color is due to lack of pigmentation, as in the pinkish-white of oculo-cutaneous albinism, or to obscuration of its pigment by blood vessels, as in the red of an abnormally vascularised iris (although human albinos generally have very light blue eyes, as the un-pigmented color of the human iris is a pale blue).

Despite the wide range of colors, there is only one pigment that contributes substantially to normal human iris color, the dark pigment called melanin. Structurally, this huge molecule is only slightly different from its equivalent found in skin and hair.

Genetic and physical factors determining iris color

Iris color is a highly complex phenomenon consisting of the combined effects of texture, pigmentation, fibrous tissue and blood vessels within the iris stroma, which together make up an individual’s epigenetic constitution. A person’s “eye color” is actually the color of one’s iris, the cornea being transparent and the white sclera entirely outside the area of interest. It is a common misconception that the iris color is entirely due to its melanin pigment, but this varies only from brown to black.

Melanin is yellowish-brown to dark brown in the stromal pigment cells, and black in the iris pigment epithelium, which lies in a thin but very opaque layer across the back of the iris. Most human irises also show a condensation of the brownish stromal melanin in the thin anterior border layer, which by its position has an overt influence on the overall color.

The degree of dispersion of the melanin, which is in subcellular bundles called melanosomes, has some influence on the observed color, but melanosomes in the iris of man and other vertebrates are not mobile, and the degree of pigment dispersion cannot be reversed.

Abnormal clumping of melanosomes does occur in disease and may lead to irreversible changes in iris color (see heterochromia, below). Colors other than brown or black are due to selective reflection and absorption from the other stromal components. Sometimes lipofuscin, a yellow “wear and tear” pigment also enters into the visible eye color, especially in aged or diseased green eyes (but not in healthy green human eyes).

Blue is one of the possible eye colors in humans. The “blue” allele, existing in the Bey2 and Gey genes of chromosome 15, is recessive. This means that both genes must have both blue alleles i.e. “blue-blue”, in a person with blue eyes. If one of the alleles were not “blue” (“green” for Gey or “brown” for Bey2) then the person would have those colored eyes respectively.

As either allele (though not both) can be passed on to offspring it is perfectly possible for someone who does not have blue eyes to have blue-eyed children. Because of its recessive nature, this is a certainty if both parents have blue eyes. Though this explanation gives an idea of eye color delineation, it is incomplete, and all the contributing factors towards eye color and its variation are not fully understood.

Faking the iris color

Certain eye colors are sometimes seen as being especially attractive and motif-expressing contact lenses can be worn to mask one’s natural eye color with another. They are rarely needed and almost never recommended by serious medical doctors, unless the patient’s retina needs extra protection, as in aniridia.

Since the introduction of machines which can automatically analyse iris patterns, and their use at some airports as a security measure, it is reported that some people have resorted to colored contact lenses, or deliberate iris injury with lasers, to prevent personal identification.

Iris color as paternity test

As stated above, although there has been much fuss about finding the genes for eye color, there is no simple genetic determinism for such a complex trait, as there is more to iris color than pigmentation. Overall, there is no simple Mendelian inheritance in iris color. Consequently no serious test of paternity can be based on observations or even measurements of iris color, except to note that blue eyes are normally phenotypically recessive, so that a brown-eyed child of two blue-eyed parents may create some doubt about paternity.

Different colors in the two eyes

Heterochromia (also known as a heterochromia iridis or heterochromia iridium) is an ocular condition in which one iris is a different color from the other iris (complete heterochromia), or where the part of one iris is a different color from the remainder (partial heterochromia or sectoral heterochromia).

Uncommon in humans, it is often an indicator of ocular disease, such as chronic iritis or diffuse iris melanoma, but may also occur as a normal variant. Sectors or patches of strikingly different colors in the same iris are less common. Alexander the Great and Anastasios the First were dubbed (dikoros, “with two pupils”) for their patent heterochromias. In their case, this was not a true dicoria (two pupils in the same iris). Real polycoria can be due to disease but is most often due to previous trauma or surgery.

In contrast, heterochromia and variegated iris patterns are common in veterinary practice. Siberian Huskies show heterochromia due to interbreeding, possibly analogous to the genetically-determined Waardenburg syndrome of humans.

Some white cat fancies (e.g., white Persians) may show striking heterochromia, with the commonest pattern being one uniformly blue, the other green. Striking variegation within the same iris is also common in some animals, and is the norm in some species.

Several herding breeds, particularly those with a blue merle coat color (such as Australian Shepherds and Border Collies) may show well-defined blue areas within a brown iris as well as separate blue and darker eyes. Some horses (usually within the white, spotted, palomino or cremello groups of breeds) may show amber, brown, white, and blue all within the same eye, without any sign of eye disease.

One eye with a white or bluish-white iris is also known as a walleye

The American Eskimo Dog Breed Great Facts

I know that you find American Eskimo dog so irresistibly cute with all those fluffy hairs and stuffs. And he can be a real charmer too, American Eskimo dogs are naturally very friendly, playful and devoted, which no doubt you’ll find a very pleasing trait for an incredibly cute dog. But, do you know all there is to know about American Eskimo dogs?

American Eskimo dogs originate from arctic regions, accounting much for its fluffy fur. A member of the Spitz dog family, American Eskimo dogs resembles in temperament much like Siberian husky and the malamute in its playfulness nature but possesses more intelligence and thus high train ability than its arctic cousins. American Eskimo dogs are also very friendly, pack oriented that is devoted to every family member and suspicious to strangers. For that they make excellent family guard dogs, barking to announce strangers but won’t attack.

These traits make American Eskimo dogs highly suited as companion dogs. Their friendly temperament compounded with their high train ability factor makes them highly prized dogs as family pets. And because they are exceedingly cute, and provides a reason for taking care of (the hair requires substantial brushing) they are top notch choices for first time owners, even children, providing companionship or functioning as therapy dogs.

American Eskimo dogs, like most dogs of the polar region require a degree of exercise or playing, especially when pups where they tend to be so playful with exhaustible energy. And the transition from pups to full grown dogs tend to be slow, so the burden of constant outdoor activities tend to be a burden for some. But this aspect could be a beneficial factor, giving an individual reason enough to sport on their runners and sweats.

The amount of hair on American Eskimo dogs can be a problem. It requires cleaning for one. Though normally American Eskimo dogs are adapted to colder climates thus having a lesser pronation to “doggy sweat” smell, they will still stink enough with dirt easily adhering to their coats. The fur underneath their eyes can stain too, with tear stain if not clean regularly. The routine to keep a clean American Eskimo dogs is therefore a shampoo once a week interspersed with coat brushing.

With regards to tick and fleas, the amount of hair on American Eskimo dogs can be a problem too. Their long hair means a bigger habitable environment for fleas, so an anti flea shampoo should be routinely used aside from regular shampoos the dog may use.

Lastly, with white fluffy hair, red lapping tongue, a few other dogs can be as cute as an American Eskimo dog at play. And playing is what they like best. So make sure if you’re bringing home an American Eskimo dog, you’re ready to spend some quality park time with him.

Fascinating Facts – Where Do Dogs Come From?

It seems most likely that our domestic dog is evolved from the wolf and that the process started around 14,000 years ago. Why? We can only guess. Maybe the wolf decided that it was in his best interests to come closer to human encampments, where he would have access to leftovers and remains.

Maybe man decided that it was good to have the wolves around, as security from other predators. Wolves could run faster than man, so teamwork between dog and man meant increased efficiency in hunting. Both benefited from this alliance, and early man developed his own breeding programme. Nervous, aggressive or independent wolves would not be selected as breeding stock. The friendliest puppies were chosen and protected, and man’s association with the dog began.

Through recent studies with foxes, it has been found that breeding for behavioural traits also affects physical characteristics. After a few generations of selective breeding, the foxes were retaining their juvenile characteristics, such as a domed head and big eyes. As we have strongly influenced the breeding of dogs through many generations, we have made substantial alterations from the basic model of the wolf, It is these changes that have enabled the dog to become the successful pet that he is today.

Physically, we have changed the wolf to suit our purposes. When looking at a German Shepherd Dog or Siberian Husky we can see some similarities, but compare the Dachshund, the Old English Sheepdog or the Great Dane and it is hard to find many resemblances. Some of the changes include:

Eye colour: many wolves have striking light-coloured eyes. ‘When a wolf looks at you, you know about it. Most dogs have brown eyes.

Noise: wolves rarely bark hut barking is one of the features that humans have selected to communicate with each other. Domestic dogs tend to howl less, but they have a whole range of other vocalizations, including barking and whining.

Contrary to popular opinion, wolves are not highly aggressive towards each other. A stable pack exists around a well defined hierarchy which allows the wolves to cooperate with each other. It would not be in the best interests of the pack for members to harm, each other.

Alaskan Klee Kai – Dog Breeds – Great Facts Everyone Should Know

In this article we will firstly look at the simple stats of this great breed, then move on to an in-depth look at whether you will be suited to this dog.

Breed group: Nordic

Weight: Toy: 10 lbs; miniature: 15 lbs; standard: 23 lbs

Height: Toy: 13 inches; miniature: inches; standard: 15-17.5 inches

Overview

The Alaskan Klee Kai have been developed by Linda Spurlin during the early part of the 1970′s in Wasilla, Alaska. After an unintentional mating between an Alaskan Husky and an unknown smaller dog, Linda Spurlin took a liking to this offspring. She ended up breeding a prototype dog that was suppose to act as a companion dog as she was so stunned with the good looks and size of these dogs. In order to reduce the size of these dogs, she developed this breed with Alaskan and Siberian Huskies – and also using American and Schipperke Eskimo Dogs in order to abolish problems with dwarfism. This breed was first known as the Klee Kai, but in 1995 the name changed to the Alaskan Klee Kai. Even today these dogs are fairly rare.

Temperament

The Alaskan Klee Kai seems to be very shy and wary of strangers, but will alert their owners by barking. These dogs are average guard dogs, and they will not attack someone seeing that they were bred to be companion dogs. But they are outstanding watch dogs, and will always alert you of something when necessary. Alaskan Klee Kais are very clever dogs that are very committed to their owners. They love the attention and company of their families. These dogs get along well other pets and children they have been raised with.

Care

This breed is average shedding dogs, and will require a brushing on a regular basis. These dogs should not be bathed too often, only when it is really necessary. Make sure that you use a good shampoo to prevent possible skin irritations. Also check the ears of the dog for too much dirt, hair or too much wax build up. Their nails can also be trimmed to keep their paws in a good condition, and to ensure that they don’t have any discomfort when walking.

Training

It is important to be consistent when training the Alaskan Klee Kai. The training environment should be fair and positive. This breed is very clever, but also very independent. Although they are compliant, they are not always obedient. But you will be glad to know that this gets better as these dogs get older. It is important to get this dogs socialised from a very early age onwards.

Health problems

Although these dogs are very tough, there have been some concerns uttered about an inherited bleeding disorder. Apart from this disorder, the Alaskan Klee Kai is fairly healthy.

Alaskan Husky – the Facts Every Owner of This Dog Breed Should Know

The Alaskan Husky is not truly a ‘breed’ of dog in the traditional sense. The name is actually a classification for this working and sled dog. There is no written breed standard for Alaskan Huskies and it is not a registered breed or show dog. Alaskan Huskies are the descendants of several dogs: Siberian Husky, Alaskan Malamute, Border Collie, German Shepard and possibly a few others.

Most Alaskan Huskies have brown eyes, but can also have blue or blue-brown combinations. They are about 20 to 24 inches high and average about 35 to 65 pounds, giving them a slim build. Since this dog is used primarily for work, colors and markings are unimportant in breeding and vary widely from dog to dog. Alaskan Huskies can be pure black, totally white and everything in between. Tails can be long and curly or barely there. The ears are often times prick ears, but some Alaskan Huskies have ears that droop.

They do not need a lot of maintenance, as their coats tend to be short to mid-length, but do require extra brushing twice a year during shedding season (particularly in the spring when shedding is the heaviest). The coats are wooly and thick (a protective measure when in their native environment) so they are better suited to cooler climates. Living on average about 10 to 15 years, the Alaskan Husky is good with children, but not other household pets as they have a strong hunting instinct and may turn on them. Though playful, loving and generally docile, the Alaskan Husky is not a good indoor pet. They can be difficult to housebreak, and get bored easily, especially if left alone. Alaskan Huskies will become destructive, tearing things or running around in circles. They also need a lot of room to run as they have a lot of energy and need to exercise frequently.

If outside, Alaskan Huskies do need to be watched closely as they will dig under fences in order to hunt or run. They also do not make good watchdogs, as they will greet everyone with friendly barking and have been known to play with any stranger entering their territory. As a result of their mixed heritage, Alaskan Huskies have relatively little health problems, though some are prone to gastric torsion (bloat) and if they do not get enough exercise will quickly become obese, leading to other health problems.

There is a website that has great information on Alaskan Huskies and most other breeds of dogs. It has details that pertain to a dog breeds health, grooming, living conditions, best food choices and more, the website is called: Dog And Cat Facts, and can be found at this url:

http://www.dogandcatfacts.com

By Robert W. Benjamin

Copyright © 2006

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