A novel method to quantify base substitution mutations at the 10^-6 per bp level in DNA samples

Area of Science:

• Genomics
• Molecular Biology
• Cancer Research

Background:

• Somatic base substitution mutations at 10^-6/bp are common in exposed tissues but difficult to measure.
• Accurate detection of rare mutations is crucial for understanding carcinogenesis and stem cell exhaustion.

Purpose of the Study:

• To develop and validate a novel method for accurately measuring rare somatic mutations at 10^-6/bp frequency.
• To enable sensitive detection of low-frequency mutations in human DNA samples.

Main Methods:

• Utilized 100 copies of genomic DNA as a template for amplicon deep sequencing.
• Selected 15,552 error-resistant base positions to reflect genome-wide mutation frequencies.
• Validated the method by detecting known low-frequency mutations and mutagen-induced mutations.

Main Results:

• Successfully detected mutations at 0.1% and mutagen-induced frequencies (4-60 x 10^-6/bp).
• Observed a decrease in non-synonymous to synonymous mutation ratios, supporting neutral theory.
• Found significantly higher mutation frequencies in gastric mucosa with Helicobacter pylori infection.

Conclusions:

• The developed method accurately measures rare base substitution mutations at the 10^-6/bp level.
• This technique is suitable for broad applications in biomedical research, including cancer and infectious disease studies.