Chapter 20, Problem 37P

Summary Introduction

To analyze:

The human melanocortin $1$ receptor gene (MC1R) plays a significant role in the production of eumelanin. Eumelanin is a black-brown pigment that helps to determine hair color and skin color. Jonathan and his colleagues studied multiple MC1R alleles in European and African populations. Though this research determined many MC1R alleles in the African population, the occurrence of $\text{MC1R}$ alleles were rare in the production of eumelanin. As compared to MC1R alleles, the other alleles were found to decrease the production of eumelanin in European populations. Illustrate how these results depict natural selection.

Introduction:

The human skin color or pigmentation results from both the parents’ genetic makeup and ultraviolet radiation. The evolution of skin shows the natural selection in order to regulate the penetration of the UV rays into the skin and also controlling its biochemical effects.

Melanin is the pigment that determines the skin color, and it is produced by melanocytes.

The $\text{MC1R}$ gene governs the production of protein melanocortico $1$ receptor. Melanocytes produces two types of melanin i.e. eumelanin and pheomelanin. The quantity of these pigments determines the skin color.

Eumelanin tends to have black or brown pigmentation, and most often, eumelanin protects skin from UV radiation in sunlight.