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Höpölöpöäs

"Human hair color

Hair color is the pigmentation of hair follicles due to two types of melanin: eumelanin and pheomelanin. Generally, if more eumelanin is present, the colour of the hair is darker; if less eumelanin is present, the hair is lighter. Levels of melanin can vary over time causing a person's hair colour to change, and it is possible to have hair follicles of more than one color on the same person.

Particular hair colors are associated with ethnic groups. The shades of human hair color are assessed using the Fischer–Saller scale. The Fischer–Saller scale, named after Eugen Fischer and Karl Saller, is used in physical anthropology and medicine to determine the shades of hair colour. The scale uses the following designations: A (very light blond), B to E (light blond), F to L (blond), M to O (dark blond), P to T (light brown to brown), U to Y (dark brown/black) and Roman numerals I to IV (red) and V to VI (red blond).[1]

Genetics and biochemistry of hair colour[edit]
See also: Human genetic variation, Race and genetics and Human genetic clustering
Two types of pigment give hair its colour: eumelanin and pheomelanin. Pheomelanin colours hair orange and red. All humans have some pheomelanin in their hair. Eumelanin, which has two subtypes of black or brown, determines the darkness of the hair colour. A low concentration of brown eumelanin results in blond hair, whereas a higher concentration of brown eumelanin results in brown hair. High amounts of black eumelanin result in black hair, while low concentrations result in gray hair.

Pheomelanin is more chemically stable than black eumelanin, but less chemically stable than brown eumelanin, so it breaks down more slowly when oxidized. This is why bleach gives darker hair a reddish tinge during the artificial colouring process. As the pheomelanin continues to break down, the hair will gradually become red, then orange, then yellow, and finally white.

The genetics of hair colors are not yet firmly established. According to one theory, at least two gene pairs control human hair color.

One phenotype (brown/blonde) has a dominant brown allele and a recessive blond allele. A person with a brown allele will have brown hair; a person with no brown alleles will be blond. This explains why two brown-haired parents can produce a blond-haired child. However, this can only be possible if both parent are heterozygous in hair color- meaning that both of them have one dominant brown hair allele and one recessive allele for blond hair, but as dominant traits mask recessive ones the parents both have brown hair. In a punnet square it is possible to determine the possibility of a certain trait in an offspring.

The other gene pair is a non-red/red pair, where the non-red allele (which suppresses production of pheomelanin) is dominant and the allele for red hair is recessive. A person with two copies of the red-haired allele will have red hair.

The two-gene model does not account for all possible shades of brown, blond, or red (for example, platinum blond versus dark blond/light brown), nor does it explain why hair color sometimes darkens as a person ages. Several gene pairs control the light versus dark hair color in a cumulative effect. A person's genotype for a multifactorial trait can interact with environment to produce varying phenotypes (see quantitative trait locus)."

Jatkoa..

Natural hair colors[edit]
Natural hair color can be black, brown, blond, red, or white.

White hair caused by albinism
Black hair[edit]
Main article: Black hair
Black hair is the darkest hair color. It has large amounts of eumelanin and is less dense than other hair colors. It can range from brown-black, blue-black or jet-black.[citation needed]

Brown hair[edit]
Main article: Brown hair
Brown hair is characterized by higher levels of eumelanin and lower levels of pheomelanin. Of the two types of eumelanin (black and brown), brown-haired people have brown eumelanin; they also usually have medium-thick strands of hair. Brown-haired girls or women are often known as brunette.

Blond hair[edit]
Main article: Blond
Blond (or blonde) hair ranges from nearly white (platinum blond, tow-haired) to a dark golden blonde. Strawberry blond, a mixture of blond and red hair, is a much rarer type containing the most pheomelanin.[citation needed]

Blond hair can have almost any proportion of pheomelanin and eumelanin, but has only small amounts of both. More pheomelanin creates a more golden or strawberry blond color, and more eumelanin creates an ash or sandy blond color. Many children born with blond hair develop darker hair as they age, with the majority of natural blonds developing a hair color of a dark "gunmetal" hue by the time they reach middle age. Pregnancy hormones hasten this process. Natural blond hair is rare in adulthood, with some reports stating that only about 2% of the world's population is naturally blond.[2] Blond hair is most commonly found in Northern and Western Europeans and their descendants but can be found spread around most of Europe. Blond hair can be found in populations in North America, South America, Israel and Australia[specify]. Studies in 2012 showed that naturally blond hair of Melanesians is caused by a recessive mutation in tyrosinase-related protein 1 (TYRP1). In the Solomon Islands, 26% of the population carry the gene; however, it is absent outside of Oceania.[3]

Auburn hair[edit]
Main article: Auburn hair
Auburn hair ranges along a spectrum of light to dark red-brown shades. The chemicals which cause auburn hair are eumelanin (brown) and pheomelanin (red), with a higher proportion of red-causing pheomelanin than is found in average brown hair. It is most commonly found in individuals of Northern and Western European descent.

Chestnut hair[edit]
Main article: Chestnut hair
Chestnut hair is a hair color which is a reddish shade of brown hair. In contrast to auburn hair, the reddish shade of chestnut is darker. Chestnut hair is common among the native peoples of Northern, Central, Western, and Eastern Europe.

Red hair[edit]
Main article: Red hair
Red hair ranges from light strawberry blond shades to titian, copper and less commonly "true" red. It is caused by a variation in the Mc1r gene and is recessive.[4] Red hair has the highest amounts of pheomelanin, around 67%, and usually low levels of eumelanin. At 1-2% of the population, it is the least common hair color in the world. It is most prominently found in Scotland, Ireland, Wales and England. Scotland has the highest proportion of redheads; 13 percent of the population has red hair and approximately 40 percent carries the recessive redhead gene.[5][6][7]

Gray and white hair[edit]
"White hair" redirects here. For the Native American leader, see White Hair. For the fictional character, see Whitehair.
Gray or white hair—sometimes colloquially called "salt and pepper" when it is 'peppered' throughout dark hair—is not caused by a true gray or white pigment, but is due to a lack of pigmentation and melanin. The clear hairs appear as gray or white because of the way light is reflected from the hairs. Gray hair color typically occurs naturally as people age (see "Aging or achromotrichia", below). For some people this can happen at a very young age (for example, at the age of 10). The same is true for children with white hair, caused by Albinism.

In some cases, gray hair may be caused by thyroid deficiencies, Waardenburg syndrome or a vitamin B12 deficiency.[8] At some point in the human life cycle, cells that are located in the base of the hair's follicles slow, and eventually stop producing pigment.[9] Piebaldism is a rare autosomal dominant disorder of melanocyte development, which may cause a congenital white forelock.[10]:867

Caucasian people often begin to gray in their twenties and early thirties while Asian people begin graying in their late thirties, but most African people retain their original hair

Jatkoa..
Jos saa liikaa maitotuotteista kalsiumia estää se kuparin imeytymisen mikä aiheuttaa kuparin puutoksen mistä seuraa tyronaasin vaje.

Kupari tekee myös rohkeaksi inhiboimalla neurotransmitteri noradrenaliinin polarisoitumista.

mitä eroa on läiskäkaljulla ja kokonaan kaljulla? Kuulapäällä läiskätauti on edennyt jo niin pitkälle että pakko ajaa loputkin pois, kun näyttäis muuten niin peikolta.
Kukapa sitä tervettä hiuskasvua pois ajelis, ettei edes sänkeä toisinaan pitäisi? Niin että siis miten ei erota?

senhuomaakunkiiltää kirjoitti:

mitä eroa on läiskäkaljulla ja kokonaan kaljulla? Kuulapäällä läiskätauti on edennyt jo niin pitkälle että pakko ajaa loputkin pois, kun näyttäis muuten niin peikolta.
Kukapa sitä tervettä hiuskasvua pois ajelis, ettei edes sänkeä toisinaan pitäisi? Niin että siis miten ei erota?

Kyllä monet nahkapäät ajelee esittäen natsi skiniä vaikka olevat kaljuja munkki homoja oikeasti. Homojen soluttautumisesta natsi porukoihin on esimerkkinä
ernest röhmhttps://fi.wikipedia.org/wiki/Ernst_Röhm
Muistuttaa muuten erästä koivuhaan "isänmaallista ulkonäöltä" :-P

Samaa se on kaikkien aineiden kohdalla, toiset ovat vain tapoja, toiset riippuvuutta aiheuttavia - tapoja nekin. Mihin muuten lasi maitoa muutaman kerran viikossa vaikuttaa ja minne pistetään määreraja?

suhteellistakohtuutta kirjoitti:

Samaa se on kaikkien aineiden kohdalla, toiset ovat vain tapoja, toiset riippuvuutta aiheuttavia - tapoja nekin. Mihin muuten lasi maitoa muutaman kerran viikossa vaikuttaa ja minne pistetään määreraja?

Maitoproteiinia ei kannata käyttää bodareitten ainakaan koska noradrenaliini vapauttaa stressihormooni kortisoolia joka estää lihaskasvun.

Maito on mammanoikien juoma ei kovisten. Vesi vanhin voitehista on se paras päällä maan. Turhaan oikeutat oraalisenfiksaation aiheuttamaa tissimaidon tarvettas ja vähättelet "käyttöannoksiasi"? :-P

suhteellistakohtuutta kirjoitti:

Samaa se on kaikkien aineiden kohdalla, toiset ovat vain tapoja, toiset riippuvuutta aiheuttavia - tapoja nekin. Mihin muuten lasi maitoa muutaman kerran viikossa vaikuttaa ja minne pistetään määreraja?

Kalsium estää kuparin imeytymisen aiheuttaen kaikenlaista kehon toimimattomuutta ja tähän on heränneet olympia yhteisönkin edustajat.

Vetyperoksidi blondeja on maa pullollaan ja sekös sairasta koska luontainen blodi tukka johtuu kivennäisaineiden puutoksesta.

En tarkastele toisten munan karvoja,mene lääkärille,

Imettäiskö nämä kalsiumia aiheuttaen kuparin puutoksen ja sitä kautta noraderenaliinin yliaktiivisuuden?
https://www.youtube.com/watch?v=Wa2aCC-1JEs