This study seeks to discover the mechanisms that evolution favored in human placentas that permit an unborn baby to grow normally, even when there is much less oxygen than is present at sea level. The hypothesis is that in people with a long evolutionary history at high altitude (Andeans), evolution has favored the development of more blood vessels and better transport of nutrients in the placenta as compared to women of sea level European ancestry. The project is important because despite profound socioeconomic disadvantages, women who are native to high altitude (Andeans, Tibetans) have larger babies and fewer complications of pregnancy than women without an evolutionary history of residence at high altitude (Europeans, Chinese). The broader merits of the proposal include international collaboration with Bolivian scientists and training of aspiring scientists in the second-poorest country in the Western Hemisphere. The study includes marginalized and under-served Native American women in this region, providing them with ultrasound and other prenatal tests not available during pregnancy for poor women living in Bolivia. From a broader scientific perspective, the results of this study will point to the placental genetic systems most subject to evolutionary natural selection under conditions of environmental adversity, and thereby inform scientists about the reasons why some babies fail to grow normally during intrauterine life, regardless of altitude.
