Ancient Gut Microbes Linked Hadza and Tsimane
Shared bacterial strains suggest microbial communities co-evolved with ancestors before global human migration.
Updated on Oct. 7, 2026 in Life Sciences
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Researchers have discovered that the Hadza people of Tanzania and the Tsimane people of the Bolivian Amazon share 1,200 gut bacterial species. This 90% overlap indicates these microbial profiles were likely transmitted over generations from common ancestors in Africa.
Why it matters
The study clarifies the deep evolutionary history of human-microbe interactions and highlights the loss of specific microbial diversity in industrialized populations. This finding explains how ancestral strains were maintained long after human groups geographically separated.
Genetic dating based on bacterial mutation rates estimates that 60% of these shared microbes are largely absent in industrialized humans. The research tracks the origins of these strains to a common ancestor approximately 17,000 years ago.
The players
Hadza
An indigenous population living in northern Tanzania known for maintaining traditional hunter-gatherer lifestyles.
Tsimane
An indigenous population residing in the Bolivian Amazon that serves as a vital model for studies on ancestral human biology.
The details
Scientists compared genetic material from stool samples to map microbial lineages across both communities. By analyzing bacterial mutation rates—the frequency at which DNA sequences change over time—the team established a timeline for when these populations diverged. Gut microbes, which assist in food digestion and immune regulation, are transmitted from mothers and household members, allowing these ancestral strains to persist across millennia despite the 7,000-mile distance between the two groups.
Timeline
17,000 years ago: Common ancestors of the identified microbial strains lived.
The Tech Race
This research expands upon the Human Microbiome Project by mapping the deep evolutionary history of bacterial symbiosis. It provides a baseline for comparing modern, industrialized microbiomes against the ancestral profiles preserved in hunter-gatherer communities.
This research sets a new benchmark for understanding the microbial baseline that once supported human health before the rise of industrialization. It informs future studies aimed at identifying if the loss of these 1,200 ancestral bacterial species drives modern inflammatory diseases.
The takeaway
The discovery proves that significant portions of the human gut ecosystem have remained remarkably stable for 17,000 years. Researchers now aim to investigate whether reintroducing these specific ancestral microbes could mitigate modern inflammatory conditions.
Further reading
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