So, I saw a girl on the stairs today with legs so white, I almost couldn't believe my eyes. When I realized that she was a redhead, I began to think about most of the other redheads I knew throughout high school. Just about all of them were extremely pale. I began to wonder why...Courtesy of Wikipedia:
Alleles that code for red hair occur close to the alleles that affect skin color, so it seems that the phenotypic expression for lighter skin and red hair are interrelated. Red hair can originate from several different changes on the MC1R-gene. If one of these changes is present on both parents' chromosomes, then the child is likely to have red hair. Even if both parents do not have red hair themselves, both can be carriers for the gene and have a redheaded child.
Red hair is also associated with pale skin due to the low concentrations of eumelanin throughout the body. A lower melanin-concentration produces the advantage that a large amount of Vitamin D can be produced under low light conditions. The down side is that when UV-radiation is strong, like around the equator, there are medical disadvantages, like higher risk of skin cancer (so wear sun screen!)
Alright, my curiosity is relieved. I feel better.
Alleles that code for red hair occur close to the alleles that affect skin color, so it seems that the phenotypic expression for lighter skin and red hair are interrelated. Red hair can originate from several different changes on the MC1R-gene. If one of these changes is present on both parents' chromosomes, then the child is likely to have red hair. Even if both parents do not have red hair themselves, both can be carriers for the gene and have a redheaded child.
Red hair is also associated with pale skin due to the low concentrations of eumelanin throughout the body. A lower melanin-concentration produces the advantage that a large amount of Vitamin D can be produced under low light conditions. The down side is that when UV-radiation is strong, like around the equator, there are medical disadvantages, like higher risk of skin cancer (so wear sun screen!)
Alright, my curiosity is relieved. I feel better.
-Caitlin
Just how many readheads did you know?
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