Limited codiversification of the gut microbiota within humans.

Limited codiversification between human and gut microbiota lineages suggests recent human history has seen minimal parallel evolution, with correlations weaker than previously thought.

• Why it matters: Understanding the extent of human-microbe coevolution is crucial for insights into microbiota diversity, health interventions, and evolutionary biology, yet existing evidence may overstate this relationship.
• What they did: The study re-analyzed phylogenetic data from human and microbial genomes, comparing correlations with unlinked human chromosomes across multiple populations, and found that geographic structure can explain observed similarities.
• The result: Findings indicate that traditional views of extensive codiversification are overstated, emphasizing the need for alternative methods to assess human-microbe coevolution and informing approaches to probiotics and diagnostics.