Quantitative analysis of DNA with single-molecule sequencing

Takahito Ohshiro,Kazumichi Yokota,Makusu Tsutsui,Masateru Taniguchi

doi:10.1038/s41598-018-26875-7

Takahito Ohshiro, Kazumichi Yokota + Show 2 more

Open Access

https://doi.org/10.1038/s41598-018-26875-7

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Abstract

Cancer can be diagnosed by identifying DNA and microRNA base sequences that have the same base length yet differ in a few base sequences, if the abundance ratios of these slightly deviant base sequences can be determined. However, such quantitative analyses cannot be performed using the current DNA sequencers. Here we determine entire base sequences of four types of DNA corresponding to the let-7 microRNA, which is a 22-base cancer marker. We record the single-molecule conductances of the base molecules using current-tunneling measurements. In addition, we count the numbers of molecules in a solution to determine the abundance ratios of two DNA strands that differ by a single base sequence.

Highlights

Genetic information has the potential to drive personalized medical treatments in the near future
Because the DNA microarray method can examine the amount of DNA and microRNA molecules with two or more known base sequences, it is widely used for disease research that relies upon DNA or microRNA19–22
Sequencing DNA that includes two types of base sequences can be realized by measuring single-molecule conductance and determining the abundance ratio in solution by counting the molecular number

Summary

Introduction

Genetic information has the potential to drive personalized medical treatments in the near future. Determination of DNA base sequences and partial amino acid sequences of peptides is possible with the measurements of the tunneling current flowing through the base molecules that are set between electrodes[23] This method of reading the difference in the electronic state of a single molecule through tunneling current does not require chemical modification of DNA or amplification by PCR because this method measures single molecules, in principle. Because the method measures individual DNA molecules, we expect that two or more base sequences can be determined by measuring a solution of DNA molecules with two or more types of base sequences Because this method can count the number of DNA molecules that contain a specific base sequence, we expect that the quantitative analysis can detect the base sequences and counts their instances

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Conclusion