Mursi Woman (IMAGE) University of Pennsylvania Caption This is a Mursi woman of Nilo-Saharan ancestry. Nilo-Saharan pastoralist populations possess some of the darkest skin in Africa. Researchers from the University of Pennsylvania found mutations associated with both light and dark pigmentation in a genome-wide association study of diverse African populations. Credit Alessia Ranciaro Usage Restrictions In context of reporting License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.