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Angela
03-03-16, 17:01
See:

https://www.theguardian.com/science/2016/mar/01/combing-human-genome-reveals-roots-of-hair-diversity

This is the actual paper:
http://www.nature.com/ncomms/2016/160301/ncomms10815/full/ncomms10815.html

"The story of human migration and evolution is written in hair DNA. In sub-Saharan Africa, genes favour tight, curly hair. But in east Asia, mutations have led to straighter, thicker hair. In Europe, other mutations brought wavy and straw-coloured hair. The changes mirror the different climates and the pressures of sexual selection."

There's a great graphic which shows the genes and snps involved for each trait.

http://www.nature.com/ncomms/2016/160301/ncomms10815/images_article/ncomms10815-f1.jpg

For hair greying, one of the culprits is a "T" at the rs12203592 snp on the IRF4 gene previously associated with red hair, I believe. I carry it, which is no surprise. I blame my father's family. My grandmother was snow white by 35. I'm sure there are other snps involved, however, and I still think stress has something to do with it. Ask anyone what it was like to have teen age children, even if they escaped other types of extreme stress. :)
https://www.snpedia.com/index.php/Rs12203592

I found this interesting:
" Primarily in Europeans; slightly lighter hair and eye color, less tanning ability"

"An Intronic Polymorphism of IRF4 Gene Influences Gene Transcription in vitro and Shows a Risk Association with Childhood Acute Lymphoblastic Leukemia in Males"

"Relationship between interferon regulatory factor 4 genetic polymorphisms, measures of sun sensitivity and risk for non-Hodgkin lymphoma "

"Potential association of single nucleotide polymorphisms in pigmentation genes with the development of basal cell carcinoma and melanoma."

I know it's probably wrong to make too much of such preliminary studies, but it all rings true from family experience. I lost my carrot haired and freckled male cousin to acute leukemia at 12, and another cousin to lymphoma. I wish my aunt and uncle were still alive. My aunt in particular tortured herself wondering if her son died so young because of something she exposed him to or something she didn't do.

As for basal cell carcinoma, it's like a family plague.

Also interesting is that they concentrate on three snps for hair color: SLC24A5, HRC2 and TYR. If it depends on the interplay between these 3, that might explain why lighter hair color often correlates with lighter hair color.

Angela
03-03-16, 19:36
It looks like the highest frequency for this hair greying gene is in the Irish, then the Komi, and there was a founder effect in the Jews.
http://alfred.med.yale.edu/alfred/mvograph.asp?siteuid=SI135310N

Phil Donohue-American talk show host. I think he once said he was this color by 30.
https://upload.wikimedia.org/wikipedia/commons/3/3f/Phil_Donahue_at_the_1989_Emmy_Awards_cropped_and_a ltered.jpg

Anderson Cooper:
http://ia.media-imdb.com/images/M/[email protected]@._ V1_UY317_CR23,0,214,317_AL_.jpg

http://media.npr.org/assets/img/2012/03/14/steve-martin_custom-018bbecdd24b0e35444d67e94f03e480a8451ab9-s6-c30.jpg

There are far fewer examples of women who greyed early and left it alone, but I happen to think it looks great on certain people depending on skin tone, cut etc. I think Meryl Streep hasn't looked this good since she was in her 20s.

http://newsstyle.com/wp-content/uploads/2015/06/Is-Meryl-Streep-to-star-in-Devil-Wears-Prada-musical-1.jpg

https://s-media-cache-ak0.pinimg.com/236x/b1/60/06/b16006ac88af922fcdae0a1bdff7d220.jpg