Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Early humans were subjected to two opposing UVR/pigmentation clines; the first (folate driven) involved melanization as one moves closer to the equator (ancestral phenotype). The second (vitamin D driven) involved depigmentation following early human expansion out of Africa and changing cultural practices (agricultural development). This second cline therefore drives depigmentation from equator to pole. This figure provides a simplified schematic view of this generalized model
