Healthy Lion Award Lecture-2014
Nina G. Jablonski is Distinguished Professor of Anthropology at The Pennsylvania State University. For the last 25 years, she has pursued questions in human evolution not directly answered by the fossil record, foremost among these being the evolution of human skin and skin pigmentation. From a primary interest in the evolution of skin pigmentation phenotypes, Jablonski has pursued issues surrounding the health and social implications of skin pigmentation. In addition to her scholarly articles on skin, Jablonski has written two popular books, Skin: A Natural History (2006) and Living Color: The Biological and Social Meaning of Skin Color (2012), both published by University of California Press. Jablonski received her A.B. in Biology at Bryn Mawr College in 1975 and her Ph.D. in Anthropology at the University of Washington in 1981. She is a Fellow of the American Association for the Advancement of Science, an elected Member of the American Philosophical Society, and a member of the Board on Behavioral, Cognitive, and Sensory Sciences of the U.S. National Research Council. She is the recipient of an Alphonse Fletcher, Sr. Fellowship (2005), a Guggenheim Fellowship (2012), and an honorary doctorate from University of Stellenbosch in South Africa (2010) for her contribution to the worldwide fight against racism. Jablonski now splits her time between basic research and educational projects. She is the lead investigator on a pilot project examining the factors that affect vitamin D status in healthy youth in the Western Cape of South Africa.
Vitamin D production in human skin is important for health and reproductive success. Maintenance of the ability to produce, utilize, and store vitamin D has involved numerous genetic changes affecting the skin and target organs during the course of human evolution. Biocultural adaptations conducive to maintenance of healthy levels of vitamin D have also been developed by human populations living under extreme environmental conditions. When paleontological, archaeological, and genetic evidence is studied with respect to information on past and present environmental conditions, notably ultraviolet radiation (UVR), hypotheses about the "vitamin D history" of the human lineage can be developed. Geographical information systems (GIS) technologies and spatial statistics can facilitate assessment of these hypotheses. Two key events constitute the basis of the "vitamin D history" of the human lineage. The first is the emergence of the human lineage and of our species under conditions of high UVR near the equator. The second is the dispersal of some human populations into regions of low and/or highly seasonal UVB. The latter event is best thought of as a series of dispersals that occurred as populations divided and entered new habitats. Adaptation to low or highly seasonal UVB involved the evolution of different skin pigmentation phenotypes, different suites of polymorphisms in genes affecting vitamin D physiology, and different diets. These adaptations were made possible by different genetic and biocultural mechanisms in different groups. The "vitamin D history" of humans is one of unique and population-specific genetic and biocultural compromises produced by natural selection and cultural evolution. These compromises are being increasingly disrupted by major changes in human lifestyles associated with rapid long-distance migrations and urbanization, with predictable negative consequences for health.The "vitamin D history" of the human lineage is complex and has involved different combinations of genetic changes and biocultural adaptations in different populations. Elucidation of these unique combinations will permit the vitamin-D-related health problems of modern people, especially those living in cities, to be effectively addressed.