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African’s skin tones

Whenever someone says Africa, the first thought on the minds of most people is a mental image of dark-skinned people. Well here is a shocker, there are many different completely natural African skin tones ranging from very dark to very light, from the Dinka of South Sudan to the San of South Africa respectively.

Different African skin tones

Africans have the most diverse skin tones in the world. Ann Gibbons in a research article published on 12th October 2017 by sciencemag.com said: “People in Africa have almost every skin colour on the planet”[1]. Sarah Tishkoff a professor in evolutionary genetics and leader of a team of scientific researchers said: “when people think of skin colour in Africa most would think of a darker skin, but we show that within Africa there is a huge amount of variation, ranging from skin as light as some Asians to the darkest skin on a global level and everything in between.”[2]

In a study conducted by a team of about 20 professional scholars from about 7 Top universities in the US including Harvard with qualifications spanning across the different fields connected with genetics and biology, they noted an extensive variation in skin pigmentation all across Africa[3]. The variation of skin tones among Africans is more diverse than across all non-African people groups. Africans with the lowest melanin levels were found to be mainly in Southern Africa and was predominantly among the San people. While individuals with the highest melanin concentration were found to be in Eastern Africa and that subset is dominated by the Nilo-Saharan Africans like the Mursi and Surma. Between these two regions consists a variety of different shades of skin tones.

These wide variants of African skin tones are due to gene variants that were recently discovered by scientists and researchers. These genes are responsible for the palette of colour tones that is widespread across Africa[4].

AFRICAN CONNECTION WITH THE WORLD

In a research study[5] that traced the evolution of these new genes, it was discovered that the dark skin of some Pacific Islanders originated from Africa, which is plausible and not surprising. The unexpected discovery, however, was that some of the gene mutations that determine the lighter skin tone of Europeans actually is of African origin. Geneticist Greg Barsh, MD, PhD of the Hudson Alpha Institute for Biotechnology, Huntsville, Alabama said: “This is really a landmark study of skin colour diversity”. Tishkoff said: “There is so much diversity in Africa that’s not often appreciated. There’s no such thing as an African race. We show that skin colour is extremely variable on the African continent and it is still evolving.”[6]

The gene responsible for the depigmentation of the skin that resulted in a pale skin called SLC24A5 that has swept across Europe for the past 6000 years was found to be commonly present in Africans. In East Africa particularly Ethiopia, more than half of the members of some Ethiopian groups were discovered to carry this SLC24A5 gene. Although they do not have white skin, it is believed that the gene is one of several that determines their skin colour. It does not stop there. Tishkoff’s team also discovered that two genes HERC2 and OCA2 carried by Europeans which determines their light skin and hair originated in Africa. It was ancient and was very common among the San people of South Africa. The team suggests that these gene variants originated in Africa hundreds of thousands of years ago.

Australian Aborigines, Melanesians and some Indians also carry these two genes, and it is believed they might have inherited them from ancient migrants from Africa.

MELANIN

In as much as there is a direct correlation between the geographical reception of ultraviolet radiation from the sun and indigenous skin pigmentation; people that are closer to the poles tend to tilt towards having lighter skin tones while people located closer to the equator tend to have darker tones. In Humans, however, there are 3 main factors that naturally determine skin colour; genetics, exposure to sun and concentration of melanin.

Different African natural skin colours

Melanin is undoubtedly the chief major factor in determining skin colour; it is a pigment produced by the body within the skin that determines skin colour, eye colour, hair colour. There are two major variants of this pigment when it comes to skin colour, Eumelanin[7] and Pheomelanin. Eumelanin is the most abundant melanin in humans and is responsible for the darker colours. Any dark-skinned human has an abundance of this pigment. It is responsible for turning the hair black. Albinism is as a result of the absence or very little presence of this pigment in an individual. Eumelanin is very effective in the absorption of ultraviolet radiation; it can dissipate about 99.9% of Ultraviolet (UV) radiation. This ability makes it able to protect skin cells. Studies have proven that Individuals with more concentration of eumelanin have a very high resistance to damage caused by UV radiation and are less likely to develop skin cancer.

Pheomelanin, on the other hand, is responsible for lighter colours, although it aids in more absorption of Vitamin D from sunlight it has a very low tolerance for UV radiation. Individuals with very light skin tones have more concentration of pheomelanin.

SKIN TONE OF HUMAN ANCESTORS

Researchers and scientists have reported that humans from all over the planet over millenniums, as they migrated and settled to areas with different intensity of UV radiation have transitioned from dark skinned to light skinned and vice versa, the transitioning process usually takes about a 100 generations or approximately 2,500 years for a full and complete skin tone change; and this happens through selective sweep[8].

It has also been reported by some scientists and historians that all modern humans share African ancestors that lived about 200,000 years ago in Africa[9] and that these African ancestors had dark skin[10]. There have been conflicting reports from researchers and scientists from all around the world regarding the skin tone of the ancestors of modern humans. Some argue that early human australopithecine ancestors had light skin “If you shave a chimpanzee, its skin is light” says Tishkoff. Others believe the ancestors of modern humans are dark skinned[11]. Whether light skinned or not there is however a common fact they all agree on, and it is that modern human ancestors were from Africa. There are suggestions that after the human ancestors shed most of their body hairs, they quickly evolved a dark skin for protection against UV radiation from the sun. Subsequent migrations from Africa to the north and south poles led to the early humans gradually transiting to a lighter skin tone as they moved further from the equator.

It is popularly believed that Africa is the first home of humans, and early human ancestors migrated to different regions of the world from Africa. What many people erroneously assume is that Africa is a continent of dark-skinned people. They are ignorant of the thousands of social groups that abound in the African continent; that are completely different from one another in culture, language, and even physical appearance. Tishkoff couldn’t have put it better when she said that, “There is no such race as the African race.”

Jason Treat and Ryan T. Williams, NGM Staff
Source: Sarah Tishkoff, University of Pennsylvania

Sources

New Gene Variants Reveal The Evolution Of Human Skin Colour. Ann Gibbons. Www.sciencemag.com. Oct 12, 2017. retrieved Feb 28, 2019.)

The Varying Skin Colours Of Africa: light, dark and all in between. Katherine Unger Baillie. Penn Today, May 24, 2014, retrieved Feb 28, 2019.

Loci Associated With Skin Pigmentation Identified In African Populations. Www.sciencemag.com. Dec 15, 2017. retrieved Feb 28, 2019.

Jablonski, Nina G. (Spring 2011). “Why Human Skin Comes in Colors”. AnthroNotes. Vol 32. retrieved 28/02/19.

Soares, P; Ermini, L; Thomson, N; Mormina, M; Rito, T; Röhl, A; Salas, A; Oppenheimer, S; MacAulay, V; Richards, M. B. (June 2009) “Correcting for purifying selection: an improved human mitochondrial molecular clock”. Am. J. Hum. Genet. 84 (6): 740–59

Rogers, Alan R.; Iltis, David; Wooding, Stephen (2004). “Genetic Variation at the MC1R Locus and the Time since Loss of Human Body Hair”. Current Anthropology. 45: 105–8.

Citations

    1. Ann Gibbons, 2017.
    2. Katherine Unger Baillie, 2014.
    3. Www.sciencemag.com.
    4. Ann Gibbons, 2017.
    5. Www.sciencemag.com.
    6. Www.sciencemag.com.
    7. Eumelanin also is of two types, black eumelanin and brown eumelanin
    8. Jablonski, Nina G. 2011.
    9. Soares, P; Ermini, L; Thomson, N; Mormina, M; Rito, T; Röhl, A; Salas, A; Oppenheimer, S; MacAulay, V; Richards, M. B. June 2009.
    10. Rogers, Alan R.; Iltis, David; Wooding, Stephen, (2004).
    11. Rogers, Alan R.; Iltis, David; Wooding, Stephen, (2004).
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