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This study analyzed gut microbiomes from 519 samples across 15 wild rodent species on two Arizona mountains to understand what determines whether gut bacteria remain specific to one host species or spread across multiple species. The researchers found that host evolutionary relationships, rather than shared environments, primarily determine bacterial strain sharing, with certain bacterial lineages showing replicated patterns of codiversification with their hosts on both mountains. Bacteria that codiversify with hosts are predominantly obligate anaerobes with optimal growth temperatures matching host body temperature, suggesting limited survival outside hosts compared to bacteria that transfer between species.
Why it matters
These findings reveal fundamental principles governing host-microbe evolution and suggest conserved constraints on microbial dispersal across mammals, with parallels to human gut microbiome patterns. The work demonstrates that long-read sequencing enables cost-effective large-scale studies of wildlife microbiomes, opening possibilities for better understanding host-microbe interactions in conservation and ecology.
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⚠️ Preprint – Noch nicht peer-reviewed
Dieser Artikel wurde noch nicht von unabhängigen Experten begutachtet. Die Ergebnisse sind vorläufig und sollten mit Vorsicht interpretiert werden.
What determines whether a gut microbial lineage has fidelity to one host species or is shared freely across multiple species? Factors that predict microbial community composition, including host species, diet, and environmental variation, have been well documented in wild animals. However, the eco-evolutionary processes maintaining host species- or population-specific microbial lineages remain unresolved. Here, we analyze 519 gut microbiome samples collected from 15 species of wild rodents across two mountains in the Madrean Sky Islands of southeastern Arizona using full-length 16S rRNA sequencing. This montane system provides a natural experiment in which adjacent replicated elevational gradients bring different combinations of rodent species into sympatry, allowing host evolutionary history to be disentangled from shared environmental effects. We find that host phylogeny, rather than environment, is the primary driver of microbial strain sharing across host species. We recover replicated signatures of codiversification on both mountains, indicating shared evolutionary history between hosts and their microbes, despite ample opportunities for cross-species environmental transmission. This evolutionary coupling is associated with predicted differences in bacterial oxygen tolerance and optimal growth temperature: codiversifying lineages are predominantly obligate anaerobes with optimal growth near host body temperature, suggesting more limited out-of-host persistence than non-codiversifying taxa. This pattern mirrors findings from the human gut microbiome, suggesting conserved constraints on microbial dispersal across mammalian hosts. The cost-effectiveness of long-read amplicon sequencing for phylogenetic inference within bacterial species opens new opportunities for large-scale evolutionary and ecological studies of host-microbe interactions in wildlife.
Source: Conserved patterns of mammal-microbe codiversification and interspecific bacterial sharing