The Color of Skin in Japanese

Abstract

I held the 48th Academic Conference of the Cosmetics Society in 2023 as president. The main theme of this conference was “pigments”. This manuscript reports the data we have obtained so far regarding the skin color of Japanese people, which is the subject of the president’s lecture. Our ancestors left Africa around 50,000 to 60,000 years ago and spread to all parts of the world. At this time, the skin color, which was originally dark, became lighter due to the relationship with vitamin D metabolism. In other words, variation in skin color occurred as genes adapted to the environment. We have clarified the genetic factors that determine the diversity of Japanese skin color. The results revealed that some variants of the gene that causes oculocutaneous albinism (OCA) have a large effect on melanin synthesis in the skin and are significantly involved in determining skin color. We also found that variation in skin color determines the risk of developing malignant melanoma. Finally, it was suggested that, as positive selection on genes, selective pressure may be at work to prevent Japanese skin color from becoming too pale and to prevent melanin production from decreasing too much.