Human Skin Color Variation

WHAT IS THE CAUSE OF HUMAN SKIN COLOR VARIATION?
ABSRTACT
This research paper deals with the causes of human skin color variation. A brief and clear explanation of skin color is first explained. Skin color is caused by a pigment called melanin. Therefore, a dark skin implies more melanin while a light skin is considered to have less melanin. In equatorial region where UV radiation is of high intensity and period, people tend to have a dark skin color. It acts as a protection against harmful sun’s rays. Near the tropics, people tend to have light colored skin. This is because they need sunlight to penetrate through the skin and enable them be able to acquire enough vitamin D which is essential to prevent diseases such as rickets. Hence since

Melanin itself is an organic polymer built from oxidative tyrosine derivatives. Both light and dark complexioned people have melanin. However, two forms are produced; pheomelanin, which is red to yellow in color, and eumelanin, which is dark brown to black. People with light complexioned skin mostly produce pheomelanin, while those with dark colored skin mostly produce eumelanin. In addition, individuals differ in the number and size of melanin particles. The latter two variables are more important in determining skin color than the percentages of the different kinds of melanin. In lighter skin, color is also affected by red cells in blood flowing close to the skin. To a lesser extent, the color is affected by the presence of fat under the skin and carotene , a reddish-orange pigment in the skin. Hair color is also due to the presence of

Only in the last decade or so has it been realistically possible to address this question experimentally using population genetic approaches. On the basis of earlier studies in mice, and on studies in humans with various Mendelian disorders, many of the genes underpinning population variation in skin color have been identified. More recently, genome-wide approaches have identified other loci that appear to contribute to pigmentary variation. The ability to study sequence diversity from world populations has allowed examination of whether the observed variability is due to random genetic drift or is a result of natural selection. The genetic evidence taken as a whole provides strong evidence for natural selection, functioning so as to increase pigment diversity across the world's populations. Future larger studies are likely to provide more details of this process and may provide evidence for exactly which mechanistic pathways have mediated selection (Jonathan & Rosalind, March 2012).

DISCUSSION OF THE CAUSES OF HUMAN SKIN COLOR VARIATIONS
The variation of human skin color is a complex phenomenon which have not yet been researched and studied conclusively. However, various researchers and academicians have given insight about the possible causes of this important trait. Different researches using people