Some of us are white, some black and some in between, but did you ever wonder how do we have these variations of colors. Why do people have different skin colors? Human skin color varies from white to almost black. The range of colors comes from the amount and type of pigment known as melanin found in the skin.
There are two types of melanin- pheomelanin and eumelanin. Generally, the more eumelanin in your skin, the darker your skin will be. People who have more amount of pheomelanin tend to have lighter skin with freckles. The kind of pigment in your skin is controlled by genes like other traits. The version has of each of these genes work together to create the final product -your skin color.
Melanin and Your Skin
Melanin is made in special cells known as melanocytes. These cells are found in the epidermis of your skin. There are three ways people can end up with different skin color. One way is that lesser the pigmentation lighter the skin. Another way is when people have fewer melanocytes. The third way is a bit more complicated and has to do with the kind of pigment someone makes. There are two types of melanin. Eumelanin is brown or black pigmentation, and pheomelanin is red or yellow pigmentation.
Skin Color Genes
Researchers have figured out that several genes that are involved in skin color. One of these genes is the melanocortin 1 receptor (MC1R). When MC1R is working well, it has melanocytes convert pheomelanin into eumelanin. If it’s not working well, then pheomelanin builds up. Most people with red hair and/or very fair skin have versions of the MC1R gene that don’t work well. That means they end up with lots of pheomelanin, which leads to lighter skin.
Scientists are studying zebrafish with light-colored stripes found another gene involved in human skin color, SLC24A5. The fish with light-colored stripes had a version of this gene that didn’t work well. When they looked in people, researchers found that some lighter-skinned people also had a poorly working version of this gene.
Why different skin colors may have evolved
People whose ancestors come from Japan and Northern Europe tend to have lighter skin than people whose ancestors are from Australia and sub-Saharan African regions. The reason for these differences may have to do with the amount of sunlight in each place. The UV light from the sun can do things like destroying folic acid or cause changes (mutations) in the DNA of some skin cells. Sometimes, these mutations may lead to skin cancer.
When our skin gets UV rays from the sun, our bodies use the UV light to make vitamin D. But melanin in our skin acts as a filter, making it harder for people with darker skin to make vitamin D. This means that more melanin you have, the more sunshine you need to make enough vitamin D.
Now we know that skin color is just a matter of how much melanin you have. The versions of the skin color genes tell your body how much melanin to make. All of this means that the difference between dark and light skin is only a few changes in DNA!