Department of Anthropology, The Pennsylvania State University, University Park, PA, USA.
Pigment Cell Melanoma Res. 2021 Jul;34(4):707-729. doi: 10.1111/pcmr.12976. Epub 2021 May 4.
The primary biological role of human skin pigmentation is as a mediator of penetration of ultraviolet radiation (UVR) into the deep layers of skin and the cutaneous circulation. Since the origin of Homo sapiens, dark, protective constitutive pigmentation and strong tanning abilities have been favored under conditions of high UVR and represent the baseline condition for modern humans. The evolution of partly depigmented skin and variable tanning abilities has occurred multiple times in prehistory, as populations have dispersed into environments with lower and more seasonal UVR regimes, with unique complements of genes and cultural practices. The evolution of extremes of dark pigmentation and depigmentation has been rare and occurred only under conditions of extremely high or low environmental UVR, promoted by positive selection on variant pigmentation genes followed by limited gene flow. Over time, the evolution of human skin pigmentation has been influenced by the nature and course of human dispersals and modifications of cultural practices, which have modified the nature and actions of skin pigmentation genes. Throughout most of prehistory and history, the evolution of human skin pigmentation has been a contingent and non-deterministic process.
人类皮肤色素的主要生物学作用是作为紫外线辐射 (UVR) 穿透皮肤深层和皮肤循环的介质。自智人出现以来，在高 UVR 条件下，深色、保护性的固有色素沉着和强烈的晒黑能力一直受到青睐，这代表了现代人的基线条件。部分脱色素皮肤和可变晒黑能力的进化在史前已经发生了多次，因为人群已经分散到 UVR 水平较低且更具季节性的环境中，具有独特的基因和文化实践的补充。极端的深色色素沉着和脱色素沉着的进化很少见，仅在极高或极低的环境 UVR 条件下发生，这是由对变异色素沉着基因的正选择以及随后有限的基因流所推动的。随着时间的推移，人类皮肤色素沉着的进化受到人类迁徙的性质和过程以及文化实践的改变的影响，这些改变改变了皮肤色素沉着基因的性质和作用。在史前和历史的大部分时间里，人类皮肤色素沉着的进化是一个偶然的、不确定的过程。
