DNA ladders: Inexpensive molecular rulers for DNA research

A schematic of pPSU1 in addition to pPSU2 plasmids. The 1000-base-pair (1 kb) ladder will be made by cutting the two plasmids with the restriction enzyme, EcoRV. The 100-base-pair (bp) ladder will be made by cutting the plasmids with PstI. Credit: Penn State University

brand new, license-free DNA ladders will allow researchers to estimate the size of fragments of DNA for a fraction of the cost of currently available methods. A research team of undergraduate students led by Penn State Professor of Biochemistry in addition to Molecular Biology Song Tan in addition to former undergraduate student Ryan C. Henrici developed two plasmids—a circular form of DNA—which can be cut by DNA scissors known as restriction enzymes to create the DNA ladders. The ladders can be used to estimate the size of DNA fragments between about 50 in addition to 5,000 base pairs in length. A paper describing the research appears online May 26, 2017 from the journal Scientific Reports.


“DNA ladders, also known as DNA molecular weight markers, are among the most commonly used reagents in molecular biology research,” said Tan. “They are used in any application which requires gel electrophoresis—a technique which separates fragments of DNA by their size. We would likely like to offer these plasmids to the research community as a means to produce high quality DNA molecular weight markers at a low cost.”

The research team created two plasmids, pPSU1 in addition to pPSU2, which together produce DNA ladders in increments of either 100 or 1,000 base pairs, depending on which restriction enzyme will be used. Researchers can easily produce in their own laboratories enough of the two ladders for 1,000 uses for under $10. In contrast, commercially available DNA ladders cost between $250 in addition to $500 for the same amount. Additionally, unlike many currently available DNA ladders, the 100-base-pair ladders work appropriately on both agarose in addition to polyacrylamide gels, two types commonly used in molecular biology.

“We are also excited about the possibility which the pPSU plasmids may be used around the entire world to further research in addition to enhance science education in classroom laboratories,” said Henrici. “which technology produces DNA ladders at less than a penny per use, a fraction of the cost of using commercially available DNA ladders.”

The pPSU1 in addition to pPSU2 plasmids used to produce the Penn State DNA ladders will be available without licensing restrictions to nonprofit academic users through the Addgene in addition to DNASU plasmid repositories.

Gel electrophoresis images of the two Penn State DNA ladders created by cutting the pPSU1 in addition to pPSU2 plasmids with restriction enzymes. The 100-base-pair (bp) ladder will be designed to be used with both agarose in addition to acrylamide gels. Credit: Penn State University


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More information:
Ryan C. Henrici et al, The pPSU Plasmids for Generating DNA Molecular Weight Markers, Scientific Reports (2017). DOI: 10.1038/s41598-017-02693-1

Journal reference:
Scientific Reports

Provided by:
Pennsylvania State University

DNA ladders: Inexpensive molecular rulers for DNA research

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