The fact that there is little diversity in the form of mc1r gene we can inferred that it is an that it is an advantageous trait to protect from extreme sun and lack of diversity is due to the negative selection.
The MC1R gene give order for formation a protein called the melanocortin 1 receptor. This receptor plays very important role in normal pigmentation. The receptor is found on the surface of melanocytes, these cells secrete a pigment called melanin. Melanin is that the pigment that gives skin, hair, and eyes their colour.
Negative selection works to get rid of deleterious alleles from a population in another term that describes this is often “purifying selection.”
Positive selection leads to directional selection. Positive selection for a beneficial allele can increase the frequency of neutral variants neighbouring the beneficial allele; such genetic hitchhiking may end in a large area of homozygosity (i.e., loss of diversity during a large area of a chromosome) due to a highly advantageous mutation and is referred to as a selective sweep.
