Summary: New genetic evidence challenges the long-held idea that humans have broadly “lost” their sense of smell. A genomic study of Indigenous Orang Asli populations in Malaysia shows that human olfaction has been actively shaped by culture, diet and environment. Hunter-gatherer groups retain highly functional, ancestral olfactory receptor genes important for foraging, while agricultural communities display genetic changes in smell receptors that appear linked to metabolic and lifestyle shifts.
This research indicates that olfactory receptor gene diversity remains evolutionarily important in humans and that subsistence strategies—how people obtain food—drive adaptive changes in our sensory systems.
Key Findings
- Distinct olfactory vocabularies: Hunter-gatherer communities often use precise, rich vocabularies to describe odors, while agricultural and urban populations more commonly describe scents by analogy (for example, “smells like a rose”).
- Metabolic connections: Among agricultural Orang Asli, a variant of the OR12D3 gene shows a distinct evolutionary pattern. This receptor is associated in prior studies with insulin metabolism, suggesting that adaptations in smell genes may have a role in processing carbohydrate-rich diets.
- Selection by subsistence: The study provides genetic evidence that how societies obtain food imposes evolutionary pressure on olfactory receptor genes.
- Refining, not losing, smell genes: Although humans did lose many olfactory receptor genes earlier in primate evolution, the remaining receptors continue to undergo strong, functionally important evolutionary change.
Source: Cell Press
Overview: From the scent of wet soil to ripe fruit, human smell receptors have been shaped over millennia by lifestyle and environment. A new study of Orang Asli communities on the Malay Peninsula demonstrates how culture and diet interact with genetics to influence olfactory receptor (OR) gene diversity.
“Many assume humans rely little on smell and that our olfactory ability steadily declined as we evolved,” says Lian Deng, corresponding author at Fudan University. “Our findings show that smell genes have continued to evolve in close response to environmental demands and cultural practices.”
Olfaction is one of the most ancient sensory systems. During human evolution from other primates, roughly 60% of olfactory receptor genes became nonfunctional. That loss has contributed to the perception that smell is less central for people. Deng and colleagues set out to explore how the remaining functional OR genes have evolved across populations with different subsistence lifestyles.
The team analyzed genomes from 50 Orang Asli individuals representing three traditional groups: Negritos (hunter-gatherers), Senoi (rotational or swidden farmers), and Proto-Malay/Jakun (horticultural and agricultural communities). They compared those genomes with data from other global populations to identify patterns linked to lifestyle and environment.
Results show that Negrito hunter-gatherers retain unusually well-preserved OR gene repertoires. Compared with many global populations that carry numerous mutations likely to reduce receptor function, Negritos have fewer damaging mutations and a higher frequency of ancestral alleles for many OR genes. These patterns suggest ongoing selection to maintain keen olfactory capability for foraging and hunting in rainforest environments.
Negritos also carry variants associated with detecting earthy, fruity and herbal odors—scents common in tropical forest habitats and associated with edible plants, roots and ripe fruit. By contrast, agricultural groups show greater diversification in OR genes, including changes in receptors with pleiotropic effects—that is, genes that influence both smell and other physiological processes.
A notable example is the Jakun subgroup, which carries a distinct variant of OR12D3. Previous research has linked OR12D3 to aspects of insulin metabolism. The study’s authors propose that as these communities shifted to carbohydrate-based agricultural diets, selection favored OR variants that also influence glucose regulation, illustrating how diet-related pressures can shape chemosensory genes indirectly through their other functions.
Overall, the findings support a model of gene-culture coevolution in which subsistence strategy guides sensory evolution: hunter-gatherers preserve ancestral olfactory repertoires for survival in complex natural environments, while agricultural transitions promote diversification through both direct chemosensory adaptation and indirect pleiotropic selection.
Questions Answered
A: Both biology and culture contribute. Survival in dense forests depends on identifying edible plants, ripe fruit, and other resources by scent. Languages and daily experience reinforce precise odor vocabularies, while urban and agricultural lifestyles treat smell as background sensory information.
A: Genetic change requires many generations. However, olfactory training and practice can improve a person’s scent discrimination and naming ability because the brain’s sensory processing is adaptable even if some genes carry mutations.
A: Many olfactory receptors are expressed outside the nose—in the gut, liver and pancreas—where they can influence nutrient sensing and metabolic pathways. Genes like OR12D3 may therefore have both chemosensory roles and metabolic effects, linking diet to selection on smell receptors.
Funding and Ethical Collaboration
- Supported by the National Key Research and Development Program of China, the National Natural Science Foundation of China, the Shanghai Science and Technology Commission Program, the Ministry of Education of China, and Fudan University.
- Study carried out in long-term collaboration with Malaysian research institutions and with support from the Ministry of Higher Education Malaysia and the Ministry of Science, Technology and Innovation of Malaysia.
- All research activities were approved by the Department of Orang Asli Development and conducted with local partnerships and oversight.
About this research
Author: Queen Muse
Source: Cell Press
Contact: Queen Muse – Cell Press
Image credit: Neuroscience News
Original Research (open access): Gene-Culture Coevolution Shapes Olfactory Receptor Gene Diversity in Orang Asli Populations — Yueyang Ma, Boon-Peng Hoh, Shuhua Xu, Lian Deng. Cell Reports. DOI: 10.1016/j.celrep.2026.117181
Abstract (condensed):
This study examines olfactory receptor gene evolution across Orang Asli groups with contrasting subsistence modes: Negrito hunter-gatherers, Senoi swidden farmers, and Jakun horticulturalists. Negritos show conserved OR gene profiles with reduced damaging mutation load and greater retention of ancestral alleles, consistent with directional selection to maintain olfactory function for foraging. Agricultural populations display diversification in OR genes, including targets with pleiotropic roles such as OR12D3 (linked to insulin regulation) and receptors associated with lung function. These patterns support a model in which subsistence strategies shape sensory evolution through intertwined genetic, cultural, and environmental pathways.