Highly efficient library preparation for Ion Torrent sequencing using Y-adapters

Library preparation is a crucial step in next-generation sequencing workflows. Key determinants of successful library preparation are the available amount of input DNA and the efficiency of the conversion of this DNA into functional library molecules. While the standard blunt-end ligation protocol for Ion Torrent libraries has a theoretical maximum efficiency of 25%, Y-adapters enable highly efficient library preparation by (i) sticky-end ligation and (ii) rendering both DNA strands functional for sequencing, hence resulting in a theoretical efficiency of up to 100%. Moreover, the generation of adapter dimers is reduced. Therefore, we designed, optimized and validated Y-adapters compatible with Ion Torrent sequencing. These facilitate higher library yields combined with overall high sequencing performance regarding the key characteristics read-length, base quality, and library complexity. METHOD SUMMARY We developed, optimized, and validated Y-adapters for Ion Torrent sequencing, which are neither commercially available nor have been described elsewhere before. These Y-adapters enable highly efficient library preparation by (i) sticky-end ligation and (ii) rendering both DNA strands, hence theoretically up to 100% of the input DNA strands are functional for sequencing. Moreover, with low DNA input, the portion of adapter dimers is substantially reduced when using the described Y-adapters.