The word "mutation" sounds scary to most people. Medicine knows many genetic diseases that burden the media, psychological disorders, dementia. Fortunately, mutations are very rare, most people happily live a full life with the "right" set of chromosomes. Sometimes mutations are harmless, giving the carrier a look.
The first people with light eyes appeared only ten thousand years ago. Primitive humans were brown-eyed. But at some point a blue-eyed baby was born with a mutated gene HERC2. Gene function is to control the level of melanin that will come to coloring the iris of the eye. Accidental "breakage," HERC2 gives a beautiful medium color of eyes blue, green shades.
A recessive gene showed admirable tenacity. Contrary to scientific theories, the mutation has not disappeared. Over time, people with blue and green eyes were born, quite often, especially in Europe. Today, almost half of Europeans (40%) – the owners of blue eyes. Green-eyed people are much rarer. On the planet only 2% of people with green eyes.
Heterochromatic is called a genetic disorder in which a person's eyes different colors. For example, one eye blue, the other brown. Effect of different eyes due to a mutation of the same gene HERC2. Only in this case the gene restricts the supply of melanin in the iris of one eye and not two, as with blue-eyed people.
Modern society in contrast to the dark middle ages ascribes "odd-eyed" people with supernatural abilities. On the contrary, they are considered attractive. Some actors and models have different eyes, what does not hinder their professional activities.
Heterochromia can be congenital or acquired. Sometimes it is a symptom of serious diseases such as waardenburg syndrome or Horner's syndrome. In the first case, there comes deafness and strabismus. Second – develop inflammatory processes, which paralyze part of the face, causing swelling.
A mutation in the gene MC1R is manifested in the growth of the child. Freckles almost never occur in infants. Previously mistakenly believed that freckles are the result of exposure to sunlight. In fact it is not.
Sometimes freckles spread beyond the face, covering the shoulders and upper back. Among the professional models are often found appealing the owners of freckles. Modern society values the natural uniqueness of the exterior.
Another failure of the same gene MC1R has given the world of people with flaming red hair. If the 16th chromosome match two recessive alleles, it will be born red-haired baby. The probability of such coincidence is extremely small. Fiery-red head have no more than 2% of the world population. Quite often, the MC1R gene is "broken" in combination with other mutations. Why red-haired people have light skin, curly hair and green eyes, which is the responsibility of a completely different gene.
A genetic disorder that is inherited. In medical circles, such a failure of delivery of melanin to the scalp called "piebaldism". Piebaldism – disorder dominant gene SNA12 or C-KIT, which possess a high degree of inheritance. There are big differences in the manifestation of genetic mutation.
It is important to remember that piebaldism manifested from birth. Itself piebaldism harmless and quite often a white strand of hair gives a special charm to the exterior. The appearance of white strands in adulthood is often a symptom of Hirschsprung disease, syndrome Waardenburg. It is noteworthy that cells devoid of pigment, retain the ability to develop it.
Sometimes there is a mutation in which eye eyelids growing one row of cilia, but two. The mutation was named "distichia". It manifests itself in early childhood and is easily diagnosed by an ophthalmologist.
Harmless mutation does look impressive. The most famous owner of a double row of eyelashes Elizabeth Taylor. In her childhood she was giving much trouble to his mother, who was mistakenly accused of embellishing eyelashes little daughter. A lush row of eyelashes served a worthy ornament cornflower eyes that tells about one mutation Elizabeth Taylor.
People, unlike animals, a double row of eyelashes do not cause discomfort. Sometimes the "spare" cilia grow perpendicular to the main, damaging the mucous membrane of the eye. The person experiences intense pain when blinking, the mucous membrane becomes inflamed. In this case, you need to consult an ophthalmologist to remove the extra eyelashes.