PT - JOURNAL ARTICLE AU - Lynn Yi AU - Lauren Liu AU - Páll Melsted AU - Lior Pachter TI - A direct comparison of genome alignment and transcriptome pseudoalignment AID - 10.1101/444620 DP - 2018 Jan 01 TA - bioRxiv PG - 444620 4099 - http://biorxiv.org/content/early/2018/10/16/444620.short 4100 - http://biorxiv.org/content/early/2018/10/16/444620.full AB - Motivation Genome alignment of reads is the first step of most genome analysis workflows. In the case of RNA-Seq, transcriptome pseudoalignment of reads is a fast alternative to genome alignment, but the different “coordinate systems” of the genome and transcriptome have made it difficult to perform direct comparisons between the approaches.Results We have developed tools for converting genome alignments to transcriptome pseudoalignments, and conversely, for projecting transcriptome pseudoalignments to genome alignments. Using these tools, we performed a direct comparison of genome alignment with transcriptome pseudoalignment. We find that both approaches produce similar quantifications. This means that for many applications genome alignment and transcriptome pseudoalignment are interchangeable.Availability and Implementation bam2tcc is a C++14 software for converting alignments in SAM/BAM format to transcript compatibility counts (TCCs) and is available at https://github.com/pachterlab/bam2tcc. kallisto genomebam is a user option of kallisto that outputs a sorted BAM file in genome coordinates as part of transcriptome pseudoalignment. The feature has been released with kallisto v0.44.0, and is available at https://pachterlab.github.io/kallisto/.Supplementary Material N/AContact Lior Pachter (lpachter{at}caltech.edu)