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.
• PCR amplification bias, caused by factors like primer mismatches and sequence properties, is a known issue.
• The impact of PCR bias on ecological diversity metrics remains unclear.

Purpose of the Study:

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

Main Methods:

• Conducting a comprehensive evaluation of PCR bias effects on diversity metrics.
• Analyzing both within-sample (alpha) and between-sample (beta) diversity.
• Utilizing theoretical and empirical insights into bias variation across ecological analyses.

Main Results:

• Perturbation-invariant diversity measures were unaffected by PCR bias.
• Widely used metrics such as Shannon diversity and Weighted-Unifrac demonstrated sensitivity to PCR bias.
• PCR-induced bias varies across different ecological analyses and community structures.

Conclusions:

• The choice of diversity metric is critical for accurate PCR-based microbial ecology.
• Certain diversity metrics are more reliable than others when dealing with PCR bias.
• Guidance is provided for applying bias-correction methods to improve the reliability of diversity analyses.