Bitter Taste Perception in BaYaka Hunter-Gatherers

Area of Science:

• Human evolutionary biology
• Sensory ecology
• Human genetics

Background:

• Bitter taste perception is a crucial human sensory trait with significant evolutionary and ecological implications.
• Understanding variation in taste perception can provide insights into human adaptation and environmental interactions.
• Previous research has highlighted genetic and environmental factors influencing bitter taste sensitivity.

Purpose of the Study:

• To investigate variations in bitter taste perception among BaYaka hunter-gatherers in the Republic of Congo.
• To compare bitter taste phenotypes between BaYaka individuals raised in distinct ecological settings: forest camps versus a logging town.
• To explore the potential influence of early-life ecological context on bitter taste perception.

Main Methods:

• Assessed bitter-tasting phenotype in 112 BaYaka individuals using phenylthiocarbamide (PTC) and thiourea taste-detection tasks.
• Classified participants based on their birth and upbringing location: forest camps or logging town.
• Employed logistic regression to analyze associations between location, sex, age, and bitter taste perception.

Main Results:

• Town-born BaYaka individuals exhibited a significantly higher likelihood of perceiving both PTC and thiourea as bitter compared to forest-born individuals.
• Odds ratios for bitter perception were 3.93 for PTC and 4.44 for thiourea in town-born versus forest-born individuals (p < 0.01 for both).
• No significant associations were observed between bitter taste perception and sex or age.

Conclusions:

• Bitter taste phenotypes differ significantly between BaYaka individuals raised in town and those from forest camps.
• Early-life ecological context appears to be a contributing factor to variations in bitter taste perception.
• Hypothesize that differential exposure to bitter plant compounds in varying environments may explain observed taste phenotype differences.