Figure 1
WGS and Targeted TELL-Seq protocols. (A) The TELL-Seq protocol was developed to assemble genomes and metagenomes, and for phasing. Although there is only one protocol, the specific amounts of starting material and TELL microbeads, as well as some aspects in the barcoding and library amplification reactions must be adjusted according to WGS applications (i.e., genomes size and sample complexity). For example, the recommended volume for the barcoding reaction is 150 μL when processing a human genome and 50 μL when processing a bacterial isolate. In this study, we propose conditions to adapt the WGS TELL-Seq protocol to the particularities of targeted applications: 1–10 (use workflow in B as reference). Based on target purity (i.e., the amount of off-target DNA or background), we anticipate two major classes of targets: largely impure targets, representing less than 1–5% of the total amount of DNA in the sample; and largely pure targets, representing 25–100% of the total amount of DNA in the sample (see Targeted Applications columns). Intermediate situations would be adjusted on a case-by-case basis, using as reference the examples provided in this study. (B) Briefly, ultra-low amounts of high-molecular weight (HMW) genomic DNA are mixed with transpososome and barcoded TELL microbeads. DNA (target for targeted applications) is then captured by transpososome and tagged. Transpososomes allow DNA recruitment on microbeads based on universal sequence homology. There are millions of microbeads in a TELL-Seq reaction, and each microbead provides a unique barcode to tagged DNA. A second transpososome complex allows tagging an intermediate position in the barcoded fragment and breaking and washing release transposase components. Barcoded DNA is finally released and amplified to build a library for sequencing.
