NCGAS makes robust transcriptome analysis easier with a readily usable workflow following de novo assembly best practices

Abstract

The National Center for Genome Analysis Support (NCGAS) assists research groups with de novo transcriptome assembly. Best practices for such analyses include sample pooling, running multiple assembler algorithms with multiple parameters, combining the assemblies, and filtering the redundancy/erroneously assembled transcripts. These combined de novo transcriptome assemblies can put a technical burden on genomic researchers who may not be fully computationally trained on efficient use of HPC clusters. NCGAS has created a workflow template to move client data through 19 parallelized assemblies using four software packages (Trinity, SOAP-denovo, transABySS, and VelvetOases) and multiple khmers. The transcripts are then combined and filtered using EviGenes to output putative transcripts and alternative forms in a replicable manner. The process is semi-automated but flexible enough to allow researchers to adjust parameters if they desire. While designed for IU machines and XSEDE’s Bridges, allocations on these machines are available to any genomics researchers in US and the job scripts can be easily adjusted for other job handlers/clusters. This workflow provides a low bar for entry into robust transcriptome assembly that follows best practices, while also providing a replicable means of filtering large numbers of transcripts into a draft version of a transcriptome. Scripts can be found at https://github.com/NCGAS/IndianaUniversity/tree/master/Transcriptome_Workflow_Mason.