![mouse-and-human-skin-cells-produce-melanin-on-a-48-hour-cycle](https://utterbuzz.com/wp-content/uploads/2019/05/mouse-and-human-skin-cells-produce-melanin-on-a-48-hour-cycle-640x413.jpg)
Researchers have discovered that mouse skin and skin cells from humans produce pigmentation in response to sunlight on a 48-hour cycle. They observed that exposing skin to ultraviolet light every two days yielded darker pigmentation with less radiation damage than daily exposure.