SuperTranscript: a data driven reference for analysis and visualisation of transcriptomes

Abstract

Numerous methods have been developed to analyse RNA sequencing data, but most rely on the availability of a reference genome, making them unsuitable for non-model organisms. De novo transcriptome assembly can build a reference transcriptome from the non-model sequencing data, but falls short of allowing most tools to be applied. Here we present superTranscripts, a simple but powerful solution to bridge that gap. SuperTranscripts are a substitute for a reference genome, consisting of all the unique exonic sequence, in transcriptional order, such that each gene is represented by a single sequence. We demonstrate how superTranscripts allow visualization, variant detection and differential isoform detection in non-model organisms, using widely applied methods that are designed to work with reference genomes. SuperTranscripts can also be applied to model organisms to enhance visualization and discover novel expressed sequence. We describe Lace, software to construct superTranscripts from any set of transcripts including de novo assembled transcriptomes. In addition we used Lace to combine reference and assembled transcriptomes for chicken and recovered the sequence of hundreds of gaps in the reference genome.