Speciation trajectories in recombining bacterial species

Area of Science:

• Evolutionary biology
• Microbial ecology
• Genetics

Background:

• Bacterial diversity is structured into cohesive units, but the drivers of this variation remain under investigation.
• Recombination's role in maintaining species coherence is known, yet the emergence of distinct clusters within species and habitat influence are poorly understood.
• Understanding bacterial speciation is crucial for classifying new species and comprehending microbial evolution.

Purpose of the Study:

• To model bacterial evolution in overlapping habitats and explore how habitat structure influences the emergence of distinct clusters.
• To investigate the impact of habitat overlap on bacterial speciation trajectories.
• To apply the developed model to real-world bacterial datasets for validation.

Main Methods:

• Development of a mathematical model simulating bacterial evolution within overlapping habitat spaces.
• Analysis of population structure outcomes based on varying degrees of habitat overlap.
• Fitting the model to genomic and ecological data from *Streptococcus pneumoniae* and *Campylobacter jejuni*.

Main Results:

• Habitat overlap dictates the evolutionary trajectory of bacterial clusters, leading to either rapid clonal divergence or stable coexistence.
• In *Streptococcus pneumoniae*, a distinct subset is maintained at a constant genetic distance via recombination.
• *Campylobacter jejuni* exhibits a minority population predicted to undergo accelerated divergence.

Conclusions:

• The degree of habitat overlap is a key factor in bacterial speciation and population structure.
• The model successfully predicts different speciation trajectories in bacterial species based on habitat characteristics.
• This framework offers a novel approach to predict and define speciation pathways in diverse bacterial populations.