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Detection of single base differences using biotinylated nucleotides with very long linker arms
K J Livak1, F W Hobbs, R J Zagursky
1Du Pont Merck Pharmaceutical Company, Experimental Station, Wilmington, DE 19880-0328.
Nucleic Acids Research
|September 25, 1992
Summary
This study enhances a primer extension method for detecting single-nucleotide differences, improving mutation and polymorphism detection. New analogs and DNA polymerase overcome previous limitations, enabling analysis of longer DNA segments.
Area of Science:
- Molecular Biology
- Genetics
Background:
- Primer extension methods detect nucleotide differences using mobility-shifting analogs.
- Previous limitations included variability from Taq DNA polymerase and a short DNA segment size limit (200 nt).
Purpose of the Study:
- To address limitations of a primer extension method for detecting nucleotide differences.
- To improve the detection of mutations and polymorphisms in longer DNA segments.
Main Methods:
- Replaced Taq DNA polymerase with Thermococcus litoralis DNA polymerase to eliminate non-templated base addition.
- Synthesized biotinylated nucleotides with long linker arms (36 atom backbone) to overcome DNA segment size limitations.
- Utilized conventional (0.4 mm) and thin (0.15 mm) sequencing gels for analysis.
Main Results:
- The modified method successfully detected mutations in human beta-hexosaminidase alpha and CYP2D6 genes in DNA segments up to 300 nt.
- Single-base polymorphisms in the human APOE gene were detected in 500-nt segments using thin gels.
- The use of Thermococcus litoralis DNA polymerase resolved variability issues.
Conclusions:
- The enhanced primer extension method effectively detects single-nucleotide differences, including mutations and polymorphisms.
- The improved technique allows for the analysis of significantly longer DNA segments than previously possible.
- This advancement offers a more robust and versatile tool for genetic variation analysis.