Host evolution shapes gut microbiome composition in Astyanax mexicanus

Area of Science:

• Ecology
• Evolutionary Biology
• Microbiome Research

Background:

• Host-microbe interactions are crucial but their evolutionary drivers are poorly understood.
• Disentangling factors like habitat and host genetics influencing microbiome composition is challenging.

Purpose of the Study:

• To investigate the impact of host habitat, genetics, and evolutionary history on gut microbiome structure.
• To compare river and cave morphotypes of Mexican tetra (Astyanax mexicanus) in natural and lab settings.

Main Methods:

• Examined gut microbiomes of wild and lab-reared Mexican tetra morphotypes.
• Analyzed microbial community structure across different habitats and evolutionary lineages.
• Utilized quantitative trait loci mapping for microbiome traits.

Main Results:

• Lab-reared fish showed higher microbiome richness and distinct composition compared to wild fish, highlighting habitat influence.
• Distinct microbiomes were observed between morphotypes even when reared under identical conditions, indicating genetic control.
• Stable differences in Fusobacteriota abundance were identified between morphotypes.

Conclusions:

• Host genetics play a significant role in shaping microbiome composition, independent of habitat.
• Cavefish evolution has led to genetic factors that influence microbial community structure.
• Fusobacteriota abundance can serve as a genetic marker for mapping the basis of microbiome composition.