The human race comprises of people with varying skin colour and tones. There are Blacks, Whites, Hispanics, Asians and many others.

Even though each race seems unique in its appearance, skin colour did in fact originate from only one place. According to ThoughtCo, a knowledge sharing platform, Africa was the origin of mankind and as such, every person had the same colour at the start.

The explanation, according to knowledge platform Science Line, is that when humans became more evolved hominids, their skin became bare. When they moved away from forests into open spaces, they were exposed to ultraviolet rays.

Ultraviolet rays provide Vitamin D which is critical for born development and healthy pregnancies. However, too much exposure to the sun results in several negative health consequences, such as skin cancer. For this reason, according to Wikipedia, an encyclopedia, exposure to UV rays trigger a person’s DNA to produce a dark pigment known as melanin whose role is to protect the skin.

The amount of sunrays that reach the surface of the earth is determined by the earth’s position to the sun. As a result, places like Africa which are close to the equator have a higher volume of direct ultraviolet rays and are thus hot, while places that are far from the equator are cold.  

When people started to migrate to colder places between 50,000 and 100,000 years ago, their mitochondrial DNA mutated in order to adapt to the climates of the places that they had moved. Over time, their descendants became lighter since they didn’t need a lot of melanin. This is according to National Geographic which investigates subjects pertaining to life.

However, people who live in coastal regions and feed on seafood have access to an alternative source of Vitamin D. This means that even without much exposure to the sun, such people can and did remain dark skinned.

The reason why the skin colour of the descendants of people who migrated changed is because ultraviolet rays (UV rays) are mutagens. Additionally, people can become dark or light skinned through natural selection. This is according to Science Mag, an online knowledge platform. For instance, if a child has a dark skinned mother and a light skinned father, they could take on either skin colour.

Up to now, human skin tone is known to change from dark to light and vice versa as people migrate. However, complete skin colour change as a result of migration happens over several generations. This is according to Science Direct.