SLC45A5 -  This is a gene which is located on chromosome 15. This gene is thought to be the cause of most of the difference in black Africans and white Europeans. This is due to only one variation in the 21420 base pair long gene. This is that one of the Alanines is changed into a Theanine, this is shown in the genetic variants of these two races. About 93+% of black Africans have the Alanine allele, where as 98+% of white Europeans have the Theanine allele. This single difference is thought to be the responsibility of the 25% – 38% change in the melanin index between the two races. The link between this gene and skin colouration was discovered while experimenting on Zebra Danios (a common fresh water tropical fish)

MC1R -  This gene is commonly known as the Agouti gene, Variations of this gene control melanogenesis – the production of melanin within living cells. This means that the gene not only controls the level of pigmentation in your skin, but it also controls the colour of your hair! The variants in red headed people cause very little melanogenesis compared to the variants in people which tan well.

These variants are also responsible for the susceptibility people have for melanoma skin cancers, increase your chances of getting freckles and solar lentigines. On the plus side, some variations of MC1R have been known to increase the amount of pain which is taken away when morphine is used.

SLC45A2 -  While this gene does not play a major part in the pigmentation of humans in general, variants of this gene can cause very dramatic changes of pigmentation. Notably oculocutaneous albinism. This is a form of albinism involving the eyes and skin, and sometimes the hair. Variants in this gene cause varying levels of disruption to melanin production; all of these variants are recessive so you may unwittingly be a carrier.