Comparing the precision of two digital PCR applications for copy number comparisons in protists

Area of Science:

• Environmental microbiology
• Molecular biology
• Eukaryotic genomics

Background:

• Accurate assessment of microbial dynamics is crucial for understanding ecosystem functions.
• Molecular techniques, particularly digital PCR (dPCR), enable sensitive quantification of microorganisms via DNA marker genes.
• Limited comparative studies exist for available dPCR platforms, hindering optimal method selection.

Purpose of the Study:

• To compare the performance and reproducibility of two leading digital PCR platforms: Bio-Rad's QX200 and QIAGEN's QIAcuity One.
• To evaluate the impact of restriction enzyme choice on gene copy number quantification.
• To assess the suitability of dPCR for analyzing unicellular eukaryote DNA in environmental contexts.

Main Methods:

• Comparative analysis of Bio-Rad QX200 and QIAGEN QIAcuity One dPCR systems.
• Use of synthetic oligonucleotides and DNA from varying cell numbers of *Paramecium tetraurelia*.
• Testing the influence of restriction enzymes (HaeIII and EcoRI) on quantification accuracy.

Main Results:

• Both dPCR platforms exhibited similar detection and quantification limits with high precision.
• The HaeIII restriction enzyme generally provided higher precision than EcoRI, particularly on the QX200 system.
• Gene copy number estimates were reproducible between platforms and showed a linear correlation with increasing cell numbers.

Conclusions:

• Cross-platform evaluations are essential for ensuring robust and reproducible gene copy number analysis in microbial ecology.
• Digital PCR platforms demonstrate significant potential for reliable environmental DNA monitoring applications.
• Standardized protocols considering factors like restriction enzyme choice can enhance dPCR accuracy.