De Novo Genome Assembly Based On Localization And Local Assembly Of Scaffolds (GABOLA)
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Chung-Yen Lin ([email protected]); LAB website
Jang-Ming Ho, Chung-Yen Lin, Shu-Hwa Chen, Yu-Jung Chang, Ping-Heng Hsieh, Po-Ying Fu, Yi-Chen Huang, Wei-Hsuan Chuang, Hsueh-Chien Cheng
GABOLA is a software designed to fill gaps in genome assemblies utilizing barcoded linked-reads generated by the 10x Genomics Chromium System. It is also compatible with long reads from TGS techniques such as PacBio SMRT Sequencing and Oxford Nanopore Technologies. Different pipelines incorporating other Gap-Filling techniques like Hybrid Scaffold by Bionano Genomics are also suggested for the optimization of genome assemblies.
Trim and sort linked-reads according to their barcodes, then align them to draft assemblies.
- Local-Contig-Based (LCB) Gap Filling: Fill intra-scaffold gaps in genome assembly with contigs de novo assembled from 10x Genomics linked reads.
- Global-Contig-Based (GCB) Gap Filling: An alternative for LCB Gap Filling. Fill intra-scaffold gaps in genome assembly using G-contigs.
- Local-Contig-Based (LCB) Scaffolding: Concatenate scaffolds with contigs de novo assembled from 10x Genomics linked reads.
- Global-Contig-Based (GCB) Scaffolding: An alternative for LCB Scaffolding. Concatenate scaffolds with G-contigs.
G-Contigs (the "G" stands for Global):
- Contigs generated by other sequence assembly software such as Supernova assembler or TGS assemblers
- Long reads from Third-Generation Sequencing.
Step 1. docker pull lsbnb/gabola:{tag}
Step 2. docker run -i -t -v $('pwd')/:/outdir/ lsbnb/gabola:{tag}
Step 3. cd outdir
The preprocess module includes three steps:
During the first part, we process the raw linked reads by taking FASTQ files created by longranger mkfastq and perform barcode processing including error correction, barcode white-listing, and attaching barcodes to reads. Then, we use TrimGalore to apply adapter and quality trimming to fastq files. After that, you can choose to trim 23-mer of R2 prefix or not. Finally, we process all fastq files to remove duplicate reads.
During the second part, we map reads to genome and filter them: We begin with aligning reads to genome scaffolds by BWA MEM or Kart. Then, we keep proper pairs by SAMBAMBA (v0.6.9). Finally, we filter the alignment by match quality calculated from CIGAR and MAPQ score.
#definition of proper pair: mapped and not (secondary_alignment or duplicate or supplementary or chimeric)
Data generated from the Preprocess module:
- A SAM file of filtered read-to-scaffold alignment (file name ends with C70M60.sam)
- Non-duplicate split reads FASTQ file path ( i.e. {outdir}/nonDup/split )
- Produce a barcode list for every gap on every scaffold from the read-to-scaffold alignment
- Assemble contigs for each gap using reads collected via barcode lists with SPAdes
- Align contigs back to the scaffolds and fill the gaps using BWA MEM.
A FASTA file containing G-contigs
Align G-contigs to scaffolds in draft assembly with BWA MEM and fill in gaps
Data generated from the Preprocess module:
- A TSV file with possible scaffold pairs and shared barcode counts (file name ends with C70M60_ScafA_ScafB_BXCnt.tsv)
- A TSV file recording barcodes on every scaffold end (file name ends with C70M60_ScafHeadTail_BX_pairSum.tsv)
- Determine candidate scaffold pairs by removing same scaffold ends and multiple end pairs
- Assemble contigs for each candidate scaffold pair using reads collected via barcode lists with SPAdes
- Find contigs crossing two ends with alignment by BWA MEM and connect scaffolds
Data generated from the Preprocess module:
- A TSV file with possible scaffold pairs and shared barcode counts (file name ends with C70M60_ScafA_ScafB_BXCnt.tsv)
- A TSV file recording barcodes on every scaffold end (file name ends with C70M60_ScafHeadTail_BX_pairSum.tsv)
- A FASTA file containing G-contigs
- Determine candidate scaffold pairs by removing same scaffold ends and multiple end pairs
- Align them to the draft assembly with minimap2
- Find G-contigs crossing two ends with alignment by minimap2 and connect scaffolds
python /opt/10x_program/runStep1to3.py -f raw_fastq_dir/ -g draft.fa --id PROJECTID -a bwa_mem -o 10x_preprocess/
/opt/LCB_GapFilling/ProduceBXList.sh -f draft_bwa_mem_C70M60.sam -a draft.fa -o LCB_GapFilling/
/opt/LCB_GapFilling/Assemble.sh -r /10x_preprocess/nonDupFq/split -o LCB_GapFilling/
/opt/LcB_GapFilling/Fill.sh -a draft.fa -o LCB_GapFilling/
It can be a stand alone module without any 10x Genomics resource.
/opt/GCB_GapFilling/Fill.sh -a draft.fa -x g-contigs.fa -o GCB_GapFilling/
#rename draft.fa by length first to fit our format
/opt/Rename_byLength.sh -a draft.fa -o LCB_Scaffolding/
python /opt/10x_program/runStep1to3.py -f raw_fastq_dir/ -g draft_rename.fa --id PROJECTID -a bwa_mem -o 10x_preprocess/
/opt/LCB_Scaffolding/CandidatePair.sh -f draft_bwa_mem_C70M60_ScafA_ScafB_BXCnt.tsv -p draft_bwa_mem_C70M60_ScafHeadTail_BX_pairSum.tsv -o LCB_Scaffolding/
/opt/LCB_Scaffolding/Assemble.sh -f draft_bwa_mem_C70M60_ScafA_ScafB_BXCnt_rmMultiEnd.tsv -r 10x_preprocess/nonDupFq/split -o LCB_Scaffolding/
/opt/LCB_Scaffolding/Scaffolding.sh -f draft_bwa_mem_C70M60_ScafA_ScafB_BXCnt_rmMultiEnd.tsv -a draft_rename.fa -o LCB_Scaffolding/
#rename draft.fa by length first to fit our format
/opt/Rename_byLength.sh -a draft.fa -o GCB_Scaffolding/
python /opt/10x_program/runStep1to3.py -f raw_fastq_dir/ -g draft_rename.fa --id PROJECTID -a bwa_mem -o 10x_preprocess/
/opt/GCB_Scaffolding/CandidatePair.sh -f draft_rename_bwa_mem_C70M60_ScafA_ScafB_BXCnt.tsv -p draft_rename_bwa_mem_C70M60_ScafHeadTail_BX_pairSum.tsv -o GCB_Scaffolding/
/opt/GCB_Scaffolding/Scaffolding.sh -f draft_gcbgf_labgf_labs_bwa_mem_C70M60_ScafA_ScafB_BXCnt_rmMultiEnd.tsv -a draft_rename.fa -x g-contigs.fa -o GCB_Scaffolding/
Our main modules can be used in any order and iterated several times. For advanced usage and suggested pipelines of our GABOLA modules please see our github website
Latest version: v1.0 , 30, July, 2021
Wei-Hsuan Chuang et.al "GABOLA: A Reliable Gap-Filling Strategy for de novo Chromosome-Level Assembly" bioRxiv (2021). doi: https://doi.org/10.1101/2021.09.07.459217
Content type
Image
Digest
Size
1.7 GB
Last updated
about 5 years ago
docker pull lsbnb/gabola:v1.0