A single molecule and long-read view of the diverse human transcriptome. Homo sapiens

The human transcriptome is extremely complex with over 100,000 transcripts presently described for ~20,000 protein coding genes. RNA sequencing has become a powerful and ubiquitous tool for understanding gene expression and for identification of individual splice junctions within transcripts1-7. However, short reads generated by current technologies do not allow a full-length view of transcript isoforms. Thus, a complete understanding of all spliced RNAs within a transcriptome is beyond our grasp and can only be inferred from a patchwork of short fragments. Sequencing full-length cDNA molecules in an amplification-free manner can yield an accurate understanding of isoform structures and their relative expression levels. Here, we employ Pacific Biosciences' long-read sequencing platform8 to investigate the isoform complement of a pool of diverse RNA-samples. We demonstrate that many novel transcripts and isoform structures exist within the human transcriptome and provide a more comprehensive and quantitative view of its true complexity.