Supporting data for "A practical DNA data storage using expanded alphabet introducing 5-methylcytosine"

DNA molecules are a promising next-generation data storage medium. Recently, it has been theoretically proposed that non-natural or modified bases can serve as extra molecular letters to increase the information density. However, the feasibility of the strategy is challenging due to the difficulty in synthesis, and the complex structure of non-natural DNA sequences. <br>Here, we describe a practical DNA data storage transcoding scheme named R+ based on the expanded molecular alphabet by introducing 5-methylcytosine (5mC). We also demonstrate the experimental validation by encoding one representative file into several 1.3~1.6 kbps <i>in vitro</i> DNA fragments for nanopore sequencing. The results show an average data recovery rate of 98.97% and 86.91% with and without reference respectively. This work validates the practicability of 5mC in DNA storage systems, with a potentially wide range of applications.