Final answer:
The gene SLC24A5 is connected to skin pigmentation and has a prevalent mutation in individuals of European descent. Skin pigmentation is an evolutionary adaptation to UV radiation that varies with geography and can change rapidly due to genetic evolution. The biological basis of race based on skin color is scientifically unfounded, as very few genetic markers determine pigmentation.
Step-by-step explanation:
Understanding Skin Pigmentation and Genetic Evolution
The SLC24A5 gene plays a crucial role in the synthesis of melanosomes, which are responsible for the variation in skin pigmentation. This gene contains a mutation that changes a single amino acid, and its homozygous mutant form is found in approximately 99% of individuals with European ancestry. The variations in skin color can be attributed to evolutionary adaptations due to different levels of exposure to ultraviolet rays. For instance, individuals living closer to the equator, where UV rays are stronger, typically have higher melanin levels to protect against sun damage. Conversely, lighter skin found in regions with less UV exposure facilitates Vitamin D production in low-light environments.
During human migration out of Africa some 40,000 years ago, darker-skinned individuals moving to Europe retained high levels of melanin, an adaptation that provided UV protection. Approximately 8,500 years ago, hunter-gatherers in parts of what is now Europe still exhibited darker skin tones. However, rapid genetic evolution linked to lighter skin pigmentation occurred, which allowed for better Vitamin D synthesis in areas with lower sunlight, such as northern Europe.
Biologically, the concept of race based solely on skin color is not scientifically valid; only a small fraction of DNA markers contribute to pigmentation. If society chose to classify individuals by alternative genetic markers such as height or blood type, our conception of race would radically change.