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Detection of a mouse H-ras codon 61 mutation using a modified allele-specific competitive blocker PCR genotypic
1Division of Genetic and Reproductive Toxicology, HFT-120, National Center for Toxicological Research, Jefferson, AR 72079, USA. bparsons@nctr.fda.gov
Mutagenesis
|December 23, 1998
Summary
A modified allele-specific competitive blocker PCR (ACB-PCR) enables sensitive detection of rare mutant alleles. This method accurately quantifies low mutant DNA fractions, crucial for genetic analysis.
Area of Science:
- Molecular Biology
- Genetics
- Biotechnology
Background:
- Detecting rare mutant alleles is challenging.
- Allele-specific competitive blocker PCR (ACB-PCR) offers a solution for genotypic selection.
- Existing methods may lack sensitivity for low mutant fractions.
Purpose of the Study:
- To develop and optimize a modified ACB-PCR method.
- To enable sensitive detection and quantification of rare mutant alleles.
- To establish conditions for concurrent detection of mutations in target and standard DNA.
Main Methods:
- Utilized preferential PCR amplification of mutant DNA with a specific primer design.
- Incorporated a blocker-primer with a 3'-terminal dideoxynucleotide to enhance sensitivity.
- Constructed an internal amplification standard (AS) DNA for accurate quantification.
Main Results:
- Successfully detected CAA-->AAA base substitution in mouse H-ras at mutant fractions as low as 10(-5).
- Optimized ACB-PCR conditions by examining dNTP concentration, blocker primer, polymerase enhancer, DNA polymerase, and annealing temperature.
- Achieved approximately equal signals from equivalent amounts of target and AS DNA over a wide range of mutant fractions (10(-1) to 10(-5)).
Conclusions:
- The modified ACB-PCR method provides a sensitive and accurate approach for genotypic selection.
- This technique is effective for quantifying low mutant DNA fractions in various applications.
- Optimized ACB-PCR facilitates reliable detection of specific genetic mutations.