A method for assembling synthetic long reads.
(a) Schematic of the approach. A supplemental barcode-pairing protocol (grey box) resolves the two distinct barcodes affixed to each original target molecule. (b) Reads associated with two distinct barcodes are shown aligned to the E. coli MG1655 reference genome. Barcode pairing merges the groups (bottom), increasing and evening the coverage and allowing assembly of the full 10-kb target sequence. (c) Length histogram of synthetic reads assembled from E. coli MG1655 genomic reads (minimum length 1 kb). The N50 length of the synthetic reads is 6.0 kb, and the longest synthetic read is 11.6 kb. (d) Mismatch rates of synthetic reads from the E. coli MG1655 dataset as a function of relative position along the synthetic read. (e) Length histogram of synthetic long reads assembled from Gelsemium sempervirens genomic reads (minimum length 1.5 kb). The N50 length of the synthetic reads is 4.3 kb. (f) An additional multiplexing index region (grey square) allows adapter-ligated samples to be mixed and processed in a single tube. Genomic DNA from twenty-four experimentally evolved strains of E. coli was separately ligated to adapters and amplified, then mixed into a single tube for the remaining steps of the protocol. E. coli genome coverage and N50 length are plotted for synthetic reads from each strain. Circle size indicates the number of short reads demultiplexed to a given strain.