Improved indel detection in DNA and RNA via realignment with ABRA2

Bioinformatics. 2019 Sep 1;35(17):2966-2973. doi: 10.1093/bioinformatics/btz033.


Motivation: Genomic variant detection from next-generation sequencing has become established as an extremely important component of research and clinical diagnoses in both cancer and Mendelian disorders. Insertions and deletions (indels) are a common source of variation and can frequently impact functionality, thus making their detection vitally important. While substantial effort has gone into detecting indels from DNA, there is still opportunity for improvement. Further, detection of indels from RNA-Seq data has largely been an afterthought and offers another critical area for variant detection.

Results: We present here ABRA2, a redesign of the original ABRA implementation that offers support for realignment of both RNA and DNA short reads. The process results in improved accuracy and scalability including support for human whole genomes. Results demonstrate substantial improvement in indel detection for a variety of data types, including those that were not previously supported by ABRA. Further, ABRA2 results in broad improvements to variant calling accuracy across a wide range of post-processing workflows including whole genomes, targeted exomes and transcriptome sequencing.

Availability and implementation: ABRA2 is implemented in a combination of Java and C/C++ and is freely available to all from:

Supplementary information: Supplementary data are available at Bioinformatics online.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • DNA
  • High-Throughput Nucleotide Sequencing
  • Humans
  • INDEL Mutation*
  • RNA*
  • Sequence Analysis, DNA*
  • Software*


  • RNA
  • DNA