Skin Pigmentation Evolution
Evolution of Skin Pigmentation due to UV Levels and Genes
Introduction
Identification of a person has long been related to the color of their skin, as skin color is the defining measure of races. There are multiple variations in skin color throughout the globe, with the differences in outward appearance ranging from dark to light. But what exactly has caused this to occur? What is the underlying event that has led to so much variation in the pigmentation of a person? What selection pressures allowed for variation in human skin color?
Answers to these questions lie in the processes of evolution. Events which have occurred over time have influenced the change in skin color. The selection of various genes with mutations throughout millennia …show more content…
Over the course of time, skin tones changed from dark to light in the new areas people inhabited, a process made possible because of a substance in the skin of humans known as melanin. Melanin is the pigment found in people which controls the color of skin [1]. It is made from two types of oxidative tyrosine derivatives, pheomelanin and eumelanin. When the amino acid, tyrosine, is oxidized by tyrosinase, melanin is synthesized in organelles called melanosomes, which vary in size, with darker toned people have more numerous, larger, and widely dispersed melanosomes [9]. Melanin controls the amount of UV radiation that can penetrate the skin, thereby protecting it from harmful rays. The more melanin a person has, the darker their skin color is. So, according to Chaplin and Jablonski, the need for more protection from the sun in areas with high levels of UV radiation will increase melanin content, leading to darker skin [1].
Shipman 2
Skin also is involved in vitamin D synthesis. As sun is absorbed into the body, vitamin D is synthesized, which is essential for humans in order for normal growth, calcium absorption, …show more content…
The lesser UV radiation also meant that less damage was being done by the sun, so not as much melanin was needed since less protection was needed [1-3]. The lightening in the skin color came as a result from mutations in certain genes. These genes included TYRP1, MATP, SLC24A5, OCA2, DCT, and
KITLG. LYST and TP53BP1 are two ancestral genes that have stayed the same over the years, keeping the production of melanin high, leading to darker skin [4-8].
Additional research is needed in order to further understanding of the evolution of human skin coloration. In today’s world, sexual selection is a strong one for humans. Men and women are choosing their mates, more often than not, based on their phenotypic appearance. It would be interesting to see how sexual selection is affecting the genes involved in skin coloration and its evolution. More research should also be done with the original findings. More people, from more areas in the world, should be studied and compared to what are believed to be the ancestral alleles from Africa. This would deepen our understanding of the evolution of skin coloration
Introduction
Identification of a person has long been related to the color of their skin, as skin color is the defining measure of races. There are multiple variations in skin color throughout the globe, with the differences in outward appearance ranging from dark to light. But what exactly has caused this to occur? What is the underlying event that has led to so much variation in the pigmentation of a person? What selection pressures allowed for variation in human skin color?
Answers to these questions lie in the processes of evolution. Events which have occurred over time have influenced the change in skin color. The selection of various genes with mutations throughout millennia …show more content…
Over the course of time, skin tones changed from dark to light in the new areas people inhabited, a process made possible because of a substance in the skin of humans known as melanin. Melanin is the pigment found in people which controls the color of skin [1]. It is made from two types of oxidative tyrosine derivatives, pheomelanin and eumelanin. When the amino acid, tyrosine, is oxidized by tyrosinase, melanin is synthesized in organelles called melanosomes, which vary in size, with darker toned people have more numerous, larger, and widely dispersed melanosomes [9]. Melanin controls the amount of UV radiation that can penetrate the skin, thereby protecting it from harmful rays. The more melanin a person has, the darker their skin color is. So, according to Chaplin and Jablonski, the need for more protection from the sun in areas with high levels of UV radiation will increase melanin content, leading to darker skin [1].
Shipman 2
Skin also is involved in vitamin D synthesis. As sun is absorbed into the body, vitamin D is synthesized, which is essential for humans in order for normal growth, calcium absorption, …show more content…
The lesser UV radiation also meant that less damage was being done by the sun, so not as much melanin was needed since less protection was needed [1-3]. The lightening in the skin color came as a result from mutations in certain genes. These genes included TYRP1, MATP, SLC24A5, OCA2, DCT, and
KITLG. LYST and TP53BP1 are two ancestral genes that have stayed the same over the years, keeping the production of melanin high, leading to darker skin [4-8].
Additional research is needed in order to further understanding of the evolution of human skin coloration. In today’s world, sexual selection is a strong one for humans. Men and women are choosing their mates, more often than not, based on their phenotypic appearance. It would be interesting to see how sexual selection is affecting the genes involved in skin coloration and its evolution. More research should also be done with the original findings. More people, from more areas in the world, should be studied and compared to what are believed to be the ancestral alleles from Africa. This would deepen our understanding of the evolution of skin coloration