The Biology of Skin Color — HHMI BioInteractive Video

biointeractive2 minutes read

Human skin color variation is explained through anthropology and genetics, with melanin playing a crucial role in protecting against UV radiation. The evolution of skin color relates to the need for protection from UV radiation and the necessity of UV for vitamin D synthesis, leading to different adaptations in various populations.

Insights

  • Skin color in humans evolved through natural selection, with darker skin near the equator and lighter skin at the poles to adapt to UV exposure levels.
  • The evolution of human skin color reflects a delicate balance between protection from UV radiation and the need for vitamin D synthesis, leading to adaptations like supplement intake in populations with limited sun exposure.

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Recent questions

  • How does human skin color vary?

    Human skin color ranges from rich, dark brown to pinkish white, with most falling in between these extremes.

  • What is the role of melanin in the skin?

    Melanin, a pigment in the skin, protects against harmful UV radiation by absorbing it, influencing the variation in human skin color.

  • Where did dark skin evolve and why?

    Dark skin evolved in equatorial Africa around 1.2 million years ago to provide a survival advantage by protecting against UV radiation, which breaks down essential nutrients like folate.

  • Why did lighter skin evolve in some populations?

    Lighter skin evolved in populations moving to higher latitudes to allow for vitamin D synthesis from UVB radiation, balancing the need for protection from UV radiation and the necessity of UV for vitamin D synthesis.

  • How do cultural adaptations impact skin color?

    Cultural adaptations, such as supplement intake, are necessary for maintaining health in dark-skinned individuals in regions with limited UV exposure, as skin color is a flexible trait influenced by evolution and independent of other physical or behavioral characteristics.

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Summary

00:00

Evolution of Human Skin Color Adaptations

  • Human skin color varies from rich, dark brown to pinkish white, with most falling in between.
  • The variation in human skin color was once a scientific mystery but is now understood through anthropology and genetics.
  • Skin color in humans evolved through natural selection, influenced by melanin in the skin.
  • Melanin, a pigment in the skin, protects against harmful UV radiation by absorbing it.
  • The distribution of skin color correlates with UV exposure, with darker skin near the equator and lighter skin at the poles.
  • Genetic studies show that dark skin evolved in equatorial Africa around 1.2 million years ago.
  • Dark skin provided a survival advantage by protecting against UV radiation, which breaks down essential nutrients like folate.
  • Lighter skin evolved in populations moving to higher latitudes to allow for vitamin D synthesis from UVB radiation.
  • Different gene variants associated with skin color evolved multiple times in various populations over the last 10,000 years.
  • The evolution of human skin color is a result of balancing the need for protection from UV radiation and the necessity of UV for vitamin D synthesis.

17:13

Vitamin D supplements for dark-skinned individuals

  • Dark-skinned individuals in regions with limited UV exposure, like Scandinavia or Minnesota, may require vitamin D supplements for optimal health due to inadequate sun exposure.
  • Cultural adaptations, such as supplement intake, are necessary for maintaining health, as skin color is a flexible trait influenced by evolution and independent of other physical or behavioral characteristics.
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