HTS (NGS) 関連のインフォマティクス情報についてまとめています。

エラーの多いロングリードをアセンブリグラフにアラインする GraphAligner







conda install -c bioconda graphaligner

GraphAligner -h

$ GraphAligner -h

GraphAligner bioconda 1.0.12-

GraphAligner bioconda 1.0.12-

Mandatory parameters:

  -g [ --graph ] arg          input graph (.gfa / .vg)

  -f [ --reads ] arg          input reads (fasta or fastq, uncompressed or 


  -a [ --alignments-out ] arg output alignment file (.gaf/.gam/.json)

  --corrected-out arg         output corrected reads file (.fa/.fa.gz)

  --corrected-clipped-out arg output corrected clipped reads file (.fa/.fa.gz)


General parameters:

  -h [ --help ]         help message

  --version             print version

  -t [ --threads ] arg  number of threads (int) (default 1)

  --verbose             print progress messages

  --E-cutoff arg        discard alignments with E-value > arg

  --all-alignments      return all alignments instead of the best 

                        non-overlapping alignments

  --extra-heuristic     use heuristics to discard more seed hits

  --try-all-seeds       don't use heuristics to discard seed hits

  --global-alignment    force the read to be aligned end-to-end even if the 

                        alignment score is poor

  --optimal-alignment   calculate the optimal alignment (VERY SLOW)



  --seeds-clustersize arg               discard seed clusters with fewer than 

                                        arg seeds (int)

  --seeds-extend-density arg            extend up to approximately the best 

                                        (arg * sequence length) seeds (double) 

                                        (-1 for all)

  --seeds-minimizer-length arg          k-mer length for minimizer seeding 


  --seeds-minimizer-windowsize arg      window size for minimizer seeding (int)

  --seeds-minimizer-density arg         keep approximately (arg * sequence 

                                        length) least common minimizers 

                                        (double) (-1 for all)

  --seeds-minimizer-ignore-frequent arg ignore arg most frequent fraction of 

                                        minimizers (double)

  --seeds-mum-count arg                 arg longest maximal unique matches 

                                        fully contained in a node (int) (-1 for


  --seeds-mem-count arg                 arg longest maximal exact matches fully

                                        contained in a node (int) (-1 for all)

  --seeds-mxm-length arg                minimum length for maximal unique / 

                                        exact matches (int)

  --seeds-mxm-cache-prefix arg          store the mum/mem seeding index to the 

                                        disk for reuse, or reuse it if it 

                                        exists (filename prefix)

  -s [ --seeds-file ] arg               external seeds (.gam)

  --seeds-first-full-rows arg           no seeding, instead calculate the first

                                        arg rows fully. VERY SLOW except on 

                                        tiny graphs (int)



  -b [ --bandwidth ] arg      alignment bandwidth (int)

  -B [ --ramp-bandwidth ] arg ramp bandwidth (int)

  -C [ --tangle-effort ] arg  tangle effort limit, higher results in slower but

                              more accurate alignments (int) (-1 for unlimited)

  --high-memory               use slightly less CPU but a lot more memory


Preset parameters:

  -x [ --preset ] arg   Preset parameters

                        dbg - Parameters optimized for de Bruijn graphs

                        vg - Parameters optimized for variation graphs




入力としてリードのfasta/fastq、アセンブリグラフとしてGFA/vgを指定する。ここではGAFフォーマット(GAF)で出力しているが、-a aln.gamを使用すると、vgと互換性のある出力が得られる。

git clone
cd GraphAligner/
GraphAligner -g test/graph.gfa -f test/read.fa -a aln.gaf -x vg
  • -g    input graph (.gfa / .vg)
  • -f     input reads (fasta or fastq, uncompressed or gzipped)
  • -a    output alignment file (.gaf/.gam/.json) 
  • -t     number of threads (int) (default 1)
  • -x     Preset parameters
    dbg - Parameters optimized for de Bruijn graphs
    vg   - Parameters optimized for variation graphs

"-x vg"は、variation graphsにリードを整列させるためのパラメータプリセットで、"-x dbg"はde brujin graphにアラインメントするプリセットになる。



Bit-parallel sequence-to-graph alignment
Mikko Rautiainen, Veli Mäkinen, Tobias Marschall
Bioinformatics, Volume 35, Issue 19, 1 October 2019, Pages 3599–3607