Neutral and selective dynamics in a synthetic microbial community.

Area of Science:

• Ecology
• Microbiology
• Evolutionary Biology

Background:

• Ecologists debate the roles of selective and neutral processes in biodiversity.
• Microbial communities are vital in health, disease, industry, and environmental processes.

Purpose of the Study:

• To investigate the transition between neutral and selective regimes in microbial communities.
• To determine how immigration and fitness differences influence this transition.
• To compare model predictions of diversity changes with experimental results.

Main Methods:

• Creation of a synthetic microbial community with heritable genetic barcodes.
• Tracking community composition over repeated subculture rounds with immigration.
• Varying the fraction of immigrants and the magnitude of fitness differences.

Main Results:

• A transition between neutral and selective regimes was observed, dependent on immigration and fitness differences.
• Neutral models predicted increased diversity with carrying capacity, while the selective model predicted a decrease.
• The experimental community lost diversity as carrying capacity increased, aligning with the selective model.

Conclusions:

• The study demonstrates a shift between neutral and selective processes in microbial communities.
• Accurate modeling of microbial community dynamics requires the inclusion of selective processes.
• Understanding these dynamics is essential for predicting responses to environmental changes.