Evolutionary Mismatches Between the Olfactory Past and Present

How is the human sense of smell shaped by the adaptive environment and subsistence regimes (e.g., hunting-gathering, pastoralism, farming, large-scale agriculture, processed foods)? And, is there a mismatch between our ancient noses and modern lifestyles? The evolutionary setting for human olfaction in Africa was lush and hunter-gatherer ancestors actively engaged with the environment throughout the day. The modern setting for human olfaction is built environments with manufactured odors and pollutants—this is true even in rural areas with high activities in farming, mining, and/or industry. My work explores the evolutionary, ecological, and adaptive underpinnings of the human sense of smell. First, I recreate the human olfactory evolutionary situation by reconstructing the noses of extinct relatives in the genus Homo (Neandertal and Denisova). The outcome of this work is to determine: 1) if members of the genus Homo have a shared olfactory repertoire that reflects our diverse global adaptations; or, 2) if humans have a singular repertoire due to our unique subsistence strategies. Second, I identify population level trends in olfactory receptor gene mutations with known linkages to odor perception. The outcome of this work is an understanding of how population level olfactory variation may impact human behavior (e.g., food preferences). Third, I look to the future of smell by exploring how modern lifestyles and anthropogenic environmental change are creating a potential evolutionary mismatch. The outcome of this work is to introduce the concept of sensory environment equity and discuss how socio-political factors create deleterious inequities. Overall, my research agenda is provide an integrated understanding of how we came to smell, what it means to smell today, and what the future brings for our noses.