You need a lot of eumelanin to absorb UV rays.

你需要大量的真色素来吸收紫。

Over the course of generations, humans living at the Sun-saturated latitudes in Africa adapted to have a higher melanin production threshold and more eumelanin, giving skin a darker tone.

数代之后生活在阳光充沛的赤道地区周围的非洲居民进化出更高的色素产生阈值，同时分泌出更多的真素加深皮肤的色调。

It comes in two broad varieties — eumelanin, which is responsible for the black and brown colours, and pheomelanin, which lends the skin and hair yellow to reddish hues.

素有两大类——真素和非素，前者使皮肤和头发呈现色和棕色，后者使皮肤和头发呈现黄色和红色。

There's eumelanin, which gives rise to a range of brown skin tones, as well as black, brown, and blond hair, and pheomelanin, which causes the reddish browns of freckles and red hair.

一种是真素，负责形成一系列棕色调皮肤以及棕和金色毛发，另一种是褐素，负责形成红棕色雀斑与红色毛发。

It gets its color from two types of melanin: brown-black eumelanin and red-yellow pheomelanin.

棕色的真色素和红黄色的褐色素。

So without enough eumelanin, you burn fast.

因此，当缺乏足够的真素时，皮肤会迅速晒伤。