Human subsistence and signatures of selection on chemosensory genes

Chemosensation (olfaction, taste) is essential for detecting and assessing foods, such that dietary shifts elicit evolutionary changes in vertebrate chemosensory genes. The transition from hunting and gathering to agriculture dramatically altered how humans acquire food. Recent genetic and linguistic studies suggest agriculture may have precipitated olfactory degeneration. Here, we explore the effects of subsistence behaviors on olfactory (OR) and taste (TASR) receptor genes among rainforest foragers and neighboring agriculturalists in Africa and Southeast Asia. We analyze 378 functional OR and 26 functional TASR genes in 133 individuals across populations in Uganda (Twa, Sua, BaKiga) and the Philippines (Agta, Mamanwa, Manobo) with differing subsistence histories. We find no evidence of relaxed selection on chemosensory genes in agricultural populations. However, we identify subsistence-related signatures of local adaptation on chemosensory genes within each geographic region. Our results highlight the importance of culture, subsistence economy, and drift in human chemosensory perception. Genetic comparison of rainforest foraging and neighboring agricultural communities in Uganda and the Philippines shows no distinction in the size of olfactory receptor gene repertoires, but there is evidence for subsistence-related local adaptation.

Automated summary

Chemosensation (olfaction, taste) is crucial for food detection and assessment, and dietary shifts can lead to evolutionary changes in vertebrate chemosensory genes. The transition from hunting and gathering to agriculture has greatly influenced human food acquisition methods. Recent studies suggest that agriculture may have caused olfactory degeneration. This research investigates the impact of subsistence behaviors on olfactory and taste receptor genes in rainforest foragers and neighboring agriculturalists in Africa and Southeast Asia, revealing signatures of local adaptation but no evidence of relaxed selection on chemosensory genes in agricultural populations.