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 successfully live a full life with the "right" set of chromosomes. Sometimes mutations are harmless, giving the media an expressive appearance.
The first people with light eyes appeared only ten thousand years ago. Primitive man was brown-eyed. But at some point, blue-eyed baby was born with a mutated gene HERC2. The function of a gene is to control the level of melanin, which will be the color of the iris of the eye. Casual "breakage" HERC2 gives the carrier a beautiful eye color blue, green colors.
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 called a genetic disorder in which a person has different colored eyes. For example, one eye blue, the other brown. The effect of different eyes due to the mutation of the same gene HERC2. Only in this case the gene restricts the supply of melanin in the iris of one eye, not two as with the blue-eyed people.
Modern society, in contrast to the dark middle ages ascribes "odd-eyed" people supernatural abilities. On the contrary, they are considered attractive. Some actors, models have different eyes, that does not prevent 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 occurs deafness and strabismus. The second is developing inflammatory processes, which paralyze the part of the face, causing swelling.
MC1R gene mutation manifests as the child grows. Freckles almost never occur in infants. Previously mistakenly believed that freckles are the result of exposure to sunlight. Actually it is not.
Sometimes freckles extend beyond the face, covering the shoulders and upper back. Among the professional models are often found attractive the owners of freckles. Modern society values the uniqueness of the natural appearance.
Another failure of the same gene MC1R has given the world of people with flaming red hair. If in the 16th chromosome match two recessive alleles that will be born red-haired baby. The probability of such a coincidence is very low. Fiery-red mane 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 this failure of delivery of melanin to the scalp called "piebaldism". Piebaldism – dominant gene disorder SNA12 or C‑KIT, which possess a high degree of inheritance. There are large differences in the manifestation of a genetic mutation.
It is important to remember that piebaldism manifests itself 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 are devoid of pigment, retain the ability to develop it.
Sometimes there is a mutation in which the eye eyelids growing one row of cilia, but two. The mutation was called "destinies". It manifests itself in early childhood and is easily diagnosed by an ophthalmologist.
Harmless mutation makes the look expressive. The most famous owner of a double row of cilia – Elizabeth Taylor. As a child, she had a lot of problems with his mother, who is wrongly accused of tinting eyelash little daughter. Lush row of eyelashes served a worthy decoration cornflower blue eyes that tells about another mutations Elizabeth Taylor.
People, unlike animals, the double row of lashes does not cause discomfort. Sometimes the "spare" cilia grow perpendicular to the main one, injuring the mucous membrane of the eye. The person experiences severe pain when blinking, the mucous membrane becomes inflamed. In this case, you need to consult an ophthalmologist to remove excess eyelashes.