PCR Bias Impacts Microbiome Ecological Analyses.

Area of Science:

• Microbial Ecology
• Molecular Biology
• Bioinformatics

Background:

• Polymerase Chain Reaction (PCR) is essential for amplicon-based microbial community profiling using marker genes like 16S rRNA.
• PCR amplification bias, caused by factors like primer mismatches and sequence properties, can skew results.
• The impact of PCR bias on ecological diversity metrics is not fully understood.

Purpose of the Study:

• To comprehensively evaluate how PCR bias influences alpha-diversity and beta-diversity in microbial communities.
• To identify which diversity metrics are robust or sensitive to PCR-induced amplification bias.
• To provide guidance on bias-correction strategies for microbial ecology studies.

Main Methods:

• Simulated and empirical datasets were used to assess PCR bias effects.
• Evaluated the impact of bias on various alpha- and beta-diversity metrics.
• Analyzed theoretical and empirical patterns of PCR bias across different community structures.

Main Results:

• Perturbation-invariant diversity measures demonstrated resilience to PCR bias.
• Widely used metrics, including Shannon diversity and Weighted-Unifrac, showed sensitivity to PCR bias.
• The degree of bias varied with ecological analyses and community composition.

Conclusions:

• The choice of diversity metric is critical for reliable PCR-based microbial ecology.
• Perturbation-invariant metrics offer a more robust approach to diversity analysis in the presence of PCR bias.
• Understanding and addressing PCR bias is crucial for accurate ecological interpretations.