Quantifying mitochondrial DNA copy number using robust regression to interpret real time PCR results

Area of Science:

• Molecular Biology
• Bioinformatics

Background:

• Real-time PCR (rtPCR) is a standard quantitative assay for DNA copy number determination.
• The [Formula: see text] method is the conventional approach for analyzing rtPCR data.
• Existing methods may introduce biases and necessitate specific experimental conditions like dilution series.

Purpose of the Study:

• To develop and evaluate an alternative data analysis method for rtPCR using robust regression.
• To assess the performance of the robust regression method compared to the standard [Formula: see text] method.
• To implement the new method as an accessible R package.

Main Methods:

• Development of a novel data analysis tool based on robust regression fitting to rtPCR signals.
• Comparative analysis of the robust regression method and the [Formula: see text] method using 96 identical PCR preparations.
• Application of rtPCR to quantify mitochondrial DNA (mtDNA) copy numbers in breast, colon, and prostate tissues (normal and tumor samples).

Main Results:

• The robust regression method yielded similar DNA copy number distributions compared to the [Formula: see text] method.
• The robust regression method eliminated the need for dilution series to estimate PCR efficiency, unlike the [Formula: see text] method.
• mtDNA copy numbers were estimated between 200-300 copies per cell across different tissue types, with slightly narrower confidence ratios using robust regression.

Conclusions:

• Robust regression provides a viable and potentially less biased alternative for rtPCR data analysis.
• The new method simplifies rtPCR experiments by removing the requirement for dilution series.
• The developed robust regression method is available as an R package for broader scientific use.