The amount of melanin found within our skin has long been a source of division for humans culturally, but anthropologist Nina Jablonski of Penn State tells the story of how human skin color unites us all biologically.
It's become one of my favorite stories to share as it relates to nutritional biology: More pigment was naturally selected because it acted as a sunscreen needed to protect against DNA damage and destruction of folate, needed for reproduction. Depigmentation was selected for when humans dispersed from Africa and into the Northern Hemisphere where they needed skin light enough to absorb sufficient UVB rays to produce vitamin D.
I first heard Jablonski discuss the nature of human skin pigmentation almost two years ago at the AAAS conference in Washington DC. Later, I discovered her TED talk, which I've posted above. It's older, but worth watching over and over again. Jablonski has a simple message: instead of using skin color to discriminate, use skin color to teach people about evolution and health.