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Coliphage M13 cloning system and ddXTP chain-termination method for DNA sequencing.
Scientia Sinica. Series B, Chemical, Biological, Agricultural, Medical & Earth Sciences
|June 1, 1986
Summary
Researchers sequenced yeast mitochondrial DNA fragments using M13 cloning and Sanger sequencing. Optimizing the insert/vector ratio enhanced recombination frequencies for efficient DNA sequencing.
Area of Science:
- Molecular Biology
- Genetics
- Biochemistry
Background:
- Mitochondrial DNA sequencing is crucial for understanding cellular respiration and genetic diversity.
- Efficient methods for DNA fragment isolation and sequencing are essential in molecular biology research.
Purpose of the Study:
- To sequence two specific DNA fragments of the cytochrome b gene from yeast mitochondrial DNA.
- To optimize the M13 cloning and Sanger sequencing methodology for improved efficiency and accuracy.
Main Methods:
- Utilized Messing's M13 cloning system with M13mp8 and M13mp9 vectors.
- Employed Sanger's dideoxynucleotide triphosphate (ddXTP) chain-termination method for sequencing.
- Transfected competent Escherichia coli JM103 cells with recombinant DNA constructs.
Main Results:
- Successfully sequenced two yeast mitochondrial DNA fragments (575 bp and 709 bp).
- Achieved high frequencies of recombination and positive recombination by maintaining a 3:1 insert/vector ratio.
- Determined that reducing the ddXTP/dXTP ratio is necessary for reading longer DNA sequences, with 394 bp read on a single X-ray film.
Conclusions:
- The M13 cloning system and Sanger sequencing are effective for analyzing yeast mitochondrial DNA.
- Optimizing the insert/vector ratio is critical for maximizing recombination efficiency.
- Adjusting nucleotide ratios in Sanger sequencing can enhance the read length of DNA fragments.