It is now well accepted that human microbiomes are actively involved in human health and changes in our microbiomes from living more sanitized and industrialized lifestyles have led to susceptibility to certain diseases. Our research group has made significant contributions in determining what exactly has changed during industrialization by characterizing the ancestral state of the human gut ecology. this talk introduces the human microbiome, molecular anthropological studies of human microbiome diversity, and the implications of such studies in understanding human health,