Paper short abstract:

We explore what role the sense of smell plays in adapting to new environments and whether chemosensory repertoires are 'tuned' to specific ecologies. We present functional data gleaned from paleogenomes coupled with ecological parameters for sensory evolution in Eurasian circumpolar hominins.

Paper long abstract:

We seek to understand how members of the genus Homo adapted differentially to novel environments following migrations out of Africa. We propose the human sense of smell is a potentially overlooked agent in these adaptations. Humans are extraordinarily sensitive to odors and surprisingly proficient at navigating by smell alone. In addition, non-human primates rely on olfaction in finding foods. We know very little about the evolutionary ecology of smell—most data are of single odor percepts in lab settings rather than natural settings that contain olfactory noise. Understanding human odor-guided behavior in the context of hominin evolutionary ecology requires we define the ecological parameters of different environments, gain functional data on receptor activity, and explore the population genetics of olfactory receptors. We present integrated data on the circumpolar region from two lines of inquiry (set against a backdrop of genetic variation): ecological parameters of smell and experimentally validated functional data for smell detection in Denisova and Altai Neandertal. These datasets allow a direct understanding of the broader evolutionary context of the hominin olfactory biology and ecology and transform our understanding of the behavioral ecology of hominins by providing a window into the timing of evolutionary adaptations in the context of ecological and geographic change. We conclude by arguing there is a critical mismatch between our evolutionary past and present by pointing to a suite of recent studies finding linkages between smell and subsistence and between modern urban settings and olfactory impairment, the consequences of which range from depression to obesity.