Question

Part A: The MC1R (melanocortin 1 receptor) gene is responsible for normal pigmentation of skin in humans and controls which kind of melanin is made by skin cells, eumelanin and/or pheomelanin. Melanin serves as a cover for the cells so harmful UV rays cannot reach the nucleus and cause mutation, but also protects folate, a type of B vitamin essential in growth and metabolism. However, there are two sides to this story: exposure to sunlight is required to convert calcium to Vitamin D, an important molecule in bone growth and absorption of essential nutrients.

1. Would you expect skin color to be plastic? Why or why not?

2. Hypothesize as to why the Inuit (Eskimo) populations have not lost their rather dark skin pigmentation?

Answer 1

Melanin made by skin cell is Eumelanin

No skin color cannot be changed through plastic surgery. Because melanin secretion is a genetic factor which cannot be chnged and in this case eumelanin is responsible for dark color and pheomelanin is responsible for reddish yellow color.

In case of eskimos they recieve large amount of reflected ultra violet ray due to snow. So due to exposure in reflected UV ray optic nerve gives signal to pituitary gland to produce more melanin.

This melanin keeps its body warm.