Redheads: (MC1R) gene on human pigmentation

[Dr. Solar Wolff]

This means, correct me if I am wrong, that there are multiple genes and multiple alleles involved in "red hair". I wonder how this information stands up the the thread linking red hair to Neanderthal inheritance?

[Euclides]

This means, correct me if I am wrong, that there are multiple genes and multiple alleles involved in "red hair". I wonder how this information stands up the the thread linking red hair to Neanderthal inheritance?

Yes, there are multiple genes and multiple alleles involved in hair color. I have read something that links red hair with cromagnons, not Neanderthal.
It´s believed that the most common mutation to red hair is 20 000 years old.

[Euclides]

J Invest Dermatol. 1998 Jul;111(1):119-22.


Comment in:
J Invest Dermatol. 1999 Apr;112(4):512-3.

Melanocortin 1 receptor variants in an Irish population.

Smith R, Healy E, Siddiqui S, Flanagan N, Steijlen PM, Rosdahl I, Jacques JP, Rogers S, Turner R, Jackson IJ, Birch-Machin MA, Rees JL.

Department of Dermatology, University of Newcastle upon Tyne, UK.

The identification of an association between variants in the human melanocortin 1 receptor (MC1R) gene and red hair and fair skin, as well as the relation between variants of this gene and coat color in animals, suggests that the MC1R is an integral control point in the normal pigmentation phenotype. In order to further define the contribution of MC1R variants to pigmentation in a normal population, we have looked for alterations in this gene in series of individuals from a general Irish population, in whom there is a preponderance of individuals with fair skin type. Seventy-five per cent contained a variant in the MC1R gene, with 30% containing two variants. The Arg151Cys, Arg160Trp, and Asp294His variants were significantly associated with red hair (p = 0.0015, p < 0.001, and p < 0.005, respectively). Importantly, no individuals harboring two of these three variants did not have red hair, although some red-haired individuals only showed one alteration. The same three variants were also over-represented in individuals with light skin type as assessed using a modified Fitzpatrick scale. Despite these associations many subjects with dark hair/darker skin type harbored MC1R variants, but there was no evidence of any particular association of variants with the darker phenotype. The Asp294His variant was similarly associated with red hair in a Dutch population, but was infrequent in red-headed subjects from Sweden. The Asp294His variant was also significantly associated with nonmelanoma skin cancer in a U.K. population. The results show that the Arg151Cys, Arg160Trp, and Asp294His variants are of key significance in determining the pigmentary phenotype and response to ultraviolet radiation, and suggest that in many cases the red-haired component and in some cases fair skin type are inherited as a Mendelian recessive.

[Vanir]

The melanocortin-1-receptor gene is the major freckle gene
Maarten Bastiaens, Jeanette ter Huurne, Nelleke Gruis, Wilma Bergman, Rudi Westendorp1, Bert-Jan Vermeer and Jan-Nico Bouwes Bavinck+

Department of Dermatology and 1Department of Clinical Epidemiology, Leiden University Medical Centre, PO Box 9600, 2300 RC Leiden, The Netherlands

Abstract

Ephelides and solar lentigines are different types of pigmented skin lesions. Ephelides appear early in childhood and are associated with fair skin type and red hair. Solar lentigines appear with increasing age and are a sign of photodamage. Both lesions are strong risk indicators for melanoma and non-melanoma skin cancer. Melanocortin-1-receptor (MC1R) gene variants are also associated with fair skin, red hair and melanoma and non-melanoma skin cancer. The purpose of this study was to investigate the relationship between MC1R gene variants, ephelides and solar lentigines. In a large case-control study, patients with melanoma and non-melanoma skin cancer and subjects without a history of skin cancer were studied. In all participants, the presence of ephelides in childhood and solar lentigines by physical examination was assessed according to strict definitions. The entire coding sequence of the MC1R gene was analyzed by single-strand conformation polymorphism analysis followed by sequence analyses. Carriers of one or two MC1R gene variants had a 3- and 11-fold increased risk of developing ephelides, respectively (both P < 0.0001), whereas the risk of developing severe solar lentigines was increased 1.5- and 2-fold (P = 0.035 and P < 0.0001), respectively. These associations were independent of skin type and hair color, and were comparable in patients with and without a history of skin cancer. The population attributable risk for ephelides to MC1R gene variants was 60%, i.e. 60% of the ephelides in the population was caused by MC1R gene variants. A dosage effect was found between the degree of ephelides and the number of MC1R gene variants. As nearly all individuals with ephelides were carriers of at least one MC1R gene variant, our data suggest that MC1R gene variants are necessary to develop ephelides. The results of the study also suggest that MC1R gene variants play a role, although less important, in the development of solar lentigines.

http://hmg.oxfordjournals.org/cgi/re...10/16/1701.pdf (155k)

[Vanir]

Even the etymology of the word freckles is unknown:
freckle 1380, probably from O.N. freknur (pl.) "freckles," of unknown origin.

And this, a little old, and probably worthless now seeing how much can change in this growing field in 4 years....

Red Hair linked to Neanderthals
Monday April 16, 2001
http://www.aulis.com/news13.htm

RED hair may be the genetic legacy of Neanderthals, scientists believe. Researchers at the John Radcliffe Institute of Molecular Medicine in Oxford say that the so-called "ginger gene" which gives
people red hair, fair skin and freckles could be up to 100,000 years old.

They claim that their discovery points to the gene having originated in Neanderthal man who lived in Europe for 200,000 years before Homo sapien settlers, the ancestors of modern man, arrived from Africa about 40,000 years ago.

Rosalind Harding, the research team leader, said: "The gene is certainly older than 50,000 years and it could be as old as 100,000 years.

"An explanation is that it comes from Neanderthals." It is estimated that at least 10 per cent of Scots have red hair and a further 40 per cent carry the gene responsible, which could account for their once
fearsome reputation as fighters.

Neanderthals have been characterised as migrant hunters and violent cannibals who probably ate most of their meat raw. They were taller and stockier than Homo sapiens, but with shorter limbs, bigger faces
and noses, receding chins and low foreheads.

The two species overlapped for a period of time and the Oxford research appears to suggests that they must have successfully interbred for the "ginger gene" to survive. Neanderthals became extinct about 28,000 years ago, the last dying out in southern Spain and southwest France.

[NeuesKaiser]

I have freckles, a lot of light red in my beard and random strains from red in my dark brown hair which keeps spreading more and more (GINGERvitis it seems) yet I tan very easily but also turn back pale just as easily. In my youth, being outdoors a lot in the southern US, my forearms and face were tan to the point no one could determine my race (German/Czech and Anglo-American) lmao but then the rest of my body looked like a ghost which confused people even more because other people as pale as me just burn. I'm also extremely resistant to cold, I use to play outside in the snow in the middle of winter even in Germany while wearing only shorts and a short sleeve shirt.

Where does this Red hair and freckles come from though? And this ability to tan? My mom and dad both only have brown hair and eyes (no freckles) and pale skin that burns, my entire dads side of the family is the same. My Grandpa on my moms side has brown eyes and hair, Grandma and the rest of that side of the family have light brown, blonde or mix of both, a lot of them being born blonde but turned brown as they grew up, they're also really pale and burn, none have freckles or red hair.