Tag Archives: assembly

Read Mapping – Mapping Illumina Data to Geoduck Genome Assemblies with Bowtie2

We have an upcoming meeting with Illumina to discuss how the geoduck genome project is coming along and to decide how we want to proceed.

So, we wanted to get a quick idea of how well our geoduck assemblies are by performing some quick alignments using Bowtie2.

Used the following assemblies as references:

  • sn_ph_01 : SuperNova assembly of 10x Genomics data

  • sparse_03 : SparseAssembler assembly of BGI and Illumina project data

  • pga_02 : Hi-C assembly of Phase Genomics data

The analysis is documented in a Jupyter Notebook.

Jupyter Notebook (GitHub):

NOTE: Due to large amount of stdout from first genome index command, the notebook does not render well on GitHub. I recommend downloading and opening notebook on a locally install version of Jupyter.

Here’s a brief overview of the process:

  1. Generate Bowtie2 indexes for each of the genome assemblies.
  2. Map 1,000,000 reads from the following Illumina NovaSeq FastQ files:


Bowtie2 Genome Indexes:

Bowtie2 sn_ph_01 alignment folder:

Bowtie2 sparse_03 alignment folder:

Bowtie2 pga_02 alignment folder:


All mapping data was pulled from the respective *.err file in the Bowtie2 alignment folders.

sequence_ID Assembler Alignment Rate (%)
sn_ph_01 SuperNova (10x) 79.89
sparse_03 SparseAssembler 85.83
pga_02 Hi-C (Phase Genomics) 79.90|

Mapping efficiency is similar for all assemblies. After speaking with Steven, we’ve decided we’ll begin exploring genome annotation pipelines.


Assembly Stats – Geoduck Genome Assembly Comparisons w/Quast – SparseAssembler, SuperNova, Hi-C

Steven requested a comparison of geoduck genome assemblies.

Ran the following Quast command:

-t 24 
--labels 20180405_sparse_kmer101,supernova_pseudohap_duck4-p,20180421_Hi-C 
/mnt/owl/Athaliana/20180419_geoduck_hi-c/Results/geoduck_roberts results 2018-04-21 18:09:04.514704/PGA_assembly.fasta

Quast output folder: results_2018_04_30_08_00_42/

Quast report (HTML): results_2018_04_30_08_00_42/report.html

The data’s pretty interesting and cool!

SparseAssembler has over 2x the amount of data (in bas pairs), yet produces the worst assembly.

SuperNova and Hi-C assemblies are very close in nearly all categories. This isn’t surprising, as the SuperNova assembly was used as a reference assembly for the Hi-C assembly.

However, the Hi-C assembly is insanely better than the SuperNova assembly! For example:

  • Largest contig is ~7x larger than the SuperNova assembly.
  • The N50 size is ~243x larger than the SuperNova assembly!!
  • L50 is only 18, 46x smaller than the SuperNova assembly!

This is pretty amazing, honestly. Even more amazing is that this data was sent over to us as some “preliminary” data for us to take a peak at!


Assembly Stats – Geoduck Hi-C Assembly Comparison

Ran the following Quast command to compare the two geoduck assemblies provided to us by Phase Genomics:

-t 24 
--labels 20180403_pga,20180421_pga 
/mnt/owl/Athaliana/20180421_geoduck_hi-c/Results/geoduck_roberts results 2018-04-03 11:05:41.596285/PGA_assembly.fasta 
/mnt/owl/Athaliana/20180421_geoduck_hi-c/Results/geoduck_roberts results 2018-04-21 18:09:04.514704/PGA_assembly.fasta

Quast Output folder: results_2018_04_30_11_16_04/

Quast report (HTML): results_2018_04_30_11_16_04/report.html

The two assemblies are nearly identical. Interesting…


Data Management – Geoduck Phase Genomics Hi-C Data

We received sequencing/assembly data from Phase Genomics.

The data contains two assemblies, produced on two different dates.

All data is here: 20180421_geoduck_hi-c

All FASTQ files (four files; Geoduck_HiC*.gz) were copied to Nightingales:

MD5 checksums were verified and appended to the Nightingales checksum file:

Nightingales sequencing inventory was updated (Google Sheet):

The two assemblies (and assembly stats) they provided are here:

I’ve updated the project-geoduck-genome GitHub wiki with this info.


Assembly – Geoduck NovaSeq using SparseAssembler (failed)

Steven came across a 2012 paper in BMC Bioinformatics (“Exploiting sparseness in de novo genome assembly”) that utilized an assembly program we hadn’t previously encountered: SparseAssembler

This software is intended to greatly reduce the required amount of RAM necessary to process very large assembly data sets. As I previously learned, RAM is a limiting factor for assembly programs, and the install (if you can even call it that) was simply upacking a zip file (program installations on Mox are not trivialso this seems like it has promise!

The job was run on our Mox node.

Here’s the batch script to initiate the job:


## Job Name
#SBATCH --job-name=20180308_sparse_assembler_geo_novaseq
## Allocation Definition 
#SBATCH --account=srlab
#SBATCH --partition=srlab
## Resources
## Nodes (We only get 1, so this is fixed)
#SBATCH --nodes=1   
## Walltime (days-hours:minutes:seconds format)
#SBATCH --time=30-00:00:00
## Memory per node
#SBATCH --mem=500G
##turn on e-mail notification
#SBATCH --mail-type=ALL
#SBATCH --mail-user=samwhite@uw.edu
## Specify the working directory for this job
#SBATCH --workdir=/gscratch/scrubbed/samwhite/20180308_SparseAssembler_novaseq_geoduck

LD 0 
NodeCovTh 1 
EdgeCovTh 0 
k 117 
g 15 
PathCovTh 100 
GS 2200000000 
i1 /gscratch/scrubbed/samwhite/20180129_trimmed_again/AD002_S9_L001_R1_001_val_1_val_1.fastq 
i2 /gscratch/scrubbed/samwhite/20180129_trimmed_again/AD002_S9_L001_R2_001_val_2_val_2.fastq 
i1 /gscratch/scrubbed/samwhite/20180129_trimmed_again/AD002_S9_L002_R1_001_val_1_val_1.fastq 
i2 /gscratch/scrubbed/samwhite/20180129_trimmed_again/AD002_S9_L002_R2_001_val_2_val_2.fastq 
i1 /gscratch/scrubbed/samwhite/20180129_trimmed_again/NR005_S4_L001_R1_001_val_1_val_1.fastq 
i2 /gscratch/scrubbed/samwhite/20180129_trimmed_again/NR005_S4_L001_R2_001_val_2_val_2.fastq 
i1 /gscratch/scrubbed/samwhite/20180129_trimmed_again/NR005_S4_L002_R1_001_val_1_val_1.fastq 
i2 /gscratch/scrubbed/samwhite/20180129_trimmed_again/NR005_S4_L002_R2_001_val_2_val_2.fastq 
i1 /gscratch/scrubbed/samwhite/20180129_trimmed_again/NR006_S3_L001_R1_001_val_1_val_1.fastq 
i2 /gscratch/scrubbed/samwhite/20180129_trimmed_again/NR006_S3_L001_R2_001_val_2_val_2.fastq 
i1 /gscratch/scrubbed/samwhite/20180129_trimmed_again/NR006_S3_L002_R1_001_val_1_val_1.fastq 
i2 /gscratch/scrubbed/samwhite/20180129_trimmed_again/NR006_S3_L002_R2_001_val_2_val_2.fastq 
i1 /gscratch/scrubbed/samwhite/20180129_trimmed_again/NR012_S1_L001_R1_001_val_1_val_1.fastq 
i2 /gscratch/scrubbed/samwhite/20180129_trimmed_again/NR012_S1_L001_R2_001_val_2_val_2.fastq 
i1 /gscratch/scrubbed/samwhite/20180129_trimmed_again/NR012_S1_L002_R1_001_val_1_val_1.fastq 
i2 /gscratch/scrubbed/samwhite/20180129_trimmed_again/NR012_S1_L002_R2_001_val_2_val_2.fastq 
i1 /gscratch/scrubbed/samwhite/20180129_trimmed_again/NR013_AD013_S2_L001_R1_001_val_1_val_1.fastq 
i2 /gscratch/scrubbed/samwhite/20180129_trimmed_again/NR013_AD013_S2_L001_R2_001_val_2_val_2.fastq 
i1 /gscratch/scrubbed/samwhite/20180129_trimmed_again/NR013_AD013_S2_L002_R1_001_val_1_val_1.fastq 
i2 /gscratch/scrubbed/samwhite/20180129_trimmed_again/NR013_AD013_S2_L002_R2_001_val_2_val_2.fastq 
i1 /gscratch/scrubbed/samwhite/20180129_trimmed_again/NR014_AD014_S5_L001_R1_001_val_1_val_1.fastq 
i2 /gscratch/scrubbed/samwhite/20180129_trimmed_again/NR014_AD014_S5_L001_R2_001_val_2_val_2.fastq 
i1 /gscratch/scrubbed/samwhite/20180129_trimmed_again/NR014_AD014_S5_L002_R1_001_val_1_val_1.fastq 
i2 /gscratch/scrubbed/samwhite/20180129_trimmed_again/NR014_AD014_S5_L002_R2_001_val_2_val_2.fastq 
i1 /gscratch/scrubbed/samwhite/20180129_trimmed_again/NR015_AD015_S6_L001_R1_001_val_1_val_1.fastq 
i2 /gscratch/scrubbed/samwhite/20180129_trimmed_again/NR015_AD015_S6_L001_R2_001_val_2_val_2.fastq 
i1 /gscratch/scrubbed/samwhite/20180129_trimmed_again/NR015_AD015_S6_L002_R1_001_val_1_val_1.fastq 
i2 /gscratch/scrubbed/samwhite/20180129_trimmed_again/NR015_AD015_S6_L002_R2_001_val_2_val_2.fastq 
i1 /gscratch/scrubbed/samwhite/20180129_trimmed_again/NR019_S7_L001_R1_001_val_1_val_1.fastq 
i2 /gscratch/scrubbed/samwhite/20180129_trimmed_again/NR019_S7_L001_R2_001_val_2_val_2.fastq 
i1 /gscratch/scrubbed/samwhite/20180129_trimmed_again/NR019_S7_L002_R1_001_val_1_val_1.fastq 
i2 /gscratch/scrubbed/samwhite/20180129_trimmed_again/NR019_S7_L002_R2_001_val_2_val_2.fastq 
i1 /gscratch/scrubbed/samwhite/20180129_trimmed_again/NR021_S8_L001_R1_001_val_1_val_1.fastq 
i2 /gscratch/scrubbed/samwhite/20180129_trimmed_again/NR021_S8_L001_R2_001_val_2_val_2.fastq 
i1 /gscratch/scrubbed/samwhite/20180129_trimmed_again/NR021_S8_L002_R1_001_val_1_val_1.fastq 
i2 /gscratch/scrubbed/samwhite/20180129_trimmed_again/NR021_S8_L002_R2_001_val_2_val_2.fastq

Output folder: 20180308_SparseAssembler_novaseq_geoduck/

Well, this failed, but not because of memory issues (which is a good start)!

Instead, it failed because the kmer size was too large??!!

See the slurm output log file:

Kmergenie had indicated a kmer size of 117bp.

Will reduce kmer size and try again. Fingers crossed…


NovaSeq Assembly – The Struggle is Real – Real Annoying!

Well, I continue to struggle to makek progress on assembling the geoduck Illumina NovaSeq data. Granted, there is a ton of data (374GB!!!!), but it’s still frustrating that we can’t get an assembly anywhere…

Here are some of the struggles so far:




  • Can’t install one of the dependencies (SOAP error correction)
  • Actually, I need to try the binary version of this, instead of the source version (the source version fails at the make step)

So, next up will trying the following two assemblers:

  • JR-Assembler: Will see if SOAPec binary will work, and then run an assembly.
  • AllPaths-LG: I was able to install this successfully on Mox.

Additionally, we’ve ordered some additional hard drives and will be converting the old head/master node on the Apple Xserve cluster to Linux. The old master node is a little better equipped than the other Apple Xserve “birds”, so will try to re-run Meraculous on it once we get it converted.


Assembly – Geoduck Illumina NovaSeq SOAPdenovo2 on Mox (FAIL)

Trying to get the NovaSeq data assembled using SOAPdenovo2 on the Mox HPC node we have and it will not work.

Tried a couple of times and it hasn’t run successfully. Here are links to the files used on Mox (including the batch script and slurm output files). I made slight changes to the formatting of the batch script because I thought there was something wrong. Specifically, the slurm output file in the 20180215 runs does not accurately reflect the command I issued (i.e. 1> ass.log is command, but slurm shows > ass.log).

NOTE: In the 20180218 run, I have excluded transferring the core dump file due to its crazy size:

Here’s the error log generated by SOAPdenovo2 in the 20180218 run (the last line is all you really need to see, though):

Version 2.04: released on July 13th, 2012
Compile May 10 2017 12:50:52


Parameters: pregraph -s /gscratch/scrubbed/samwhite/20180218_soapdenovo2_novaseq_geoduck/soap_config -K 117 -p 24 -o /gscratch/scrubbed/samwhite/20180218_soapdenovo2_novaseq_geoduck/ 

In /gscratch/scrubbed/samwhite/20180218_soapdenovo2_novaseq_geoduck/soap_config, 1 lib(s), maximum read length 150, maximum name length 256.

24 thread(s) initialized.
Import reads from file:
Import reads from file:
--- 100000000th reads.
--- 200000000th reads.
--- 300000000th reads.
Import reads from file:
Import reads from file:
--- 400000000th reads.
--- 500000000th reads.
--- 600000000th reads.
--- 700000000th reads.
Import reads from file:
Import reads from file:
Import reads from file:
Import reads from file:
Import reads from file:
Import reads from file:
Import reads from file:
Import reads from file:
Import reads from file:
Import reads from file:
Import reads from file:
Import reads from file:
Import reads from file:
Import reads from file:
--- 800000000th reads.
--- 900000000th reads.
-- Out of memory --

I guess I’ll explore some other options for assembling these? I’m having a difficult time accepting that 500GB of RAM is insufficient, but that seems to be the case. Ouch.


NovaSeq Assembly – Trimmed Geoduck NovaSeq with Meraculous

Attempted to use Meraculous to assemble the trimmed geoduck NovaSeq data.

Here’s the Meraculous manual (PDF).

After a bunch of various issues (running out of hard drive space – multiple times, config file issues, typos), I’ve finally given up on running meraculous. It failed, again, saying it couldn’t find a file in a directory that meraculous created! I’ve emailed the authors and if they have an easy fix, I’ll implement it and see what happens.

Anyway, it’s all documented in the Jupyter Notebook below.

One good thing came out of all of it is that I had to run kmergenie to identify an appopriate kmer size to use for assembly, as well as estimated genome size (this info is needed for both meraculous and SOAPdeNovo (which I’ll be trying next)):

kmergenie output folder: http://owl.fish.washington.edu/Athaliana/20180125_geoduck_novaseq/20180206_kmergenie/
kmergenie HTML report (doesn’t display histograms for some reason): 20180206_kmergenie/histograms_report.html
kmer size: 117
Est. genome size: 2.17Gbp

Jupyter Notebook (GitHub): 20180205_roadrunner_meraculous_geoduck_novaseq.ipynb


Assembly Comparisons – Oly Assemblies Using Quast

I ran Quast to compare all of our current Olympia oyster genome assemblies.

See Jupyter Notebook in Results section for Quast execution.


Output folder: http://owl.fish.washington.edu/Athaliana/quast_results/results_2018_01_16_10_08_35/

Heatmapped table of results: http://owl.fish.washington.edu/Athaliana/quast_results/results_2018_01_16_10_08_35/report.html

Very enlightening!

After all the difficulties with PB Jelly, it has produced the most large contigs. However, it does also have the highest quantity and rate of N’s of all the assemblies produced to date.


contigs (>= 50000 bp): pbjelly_sjw_01 (894)

Largest Contig: redundans_sjw_02 (322,397bp)
Total Length: pbjelly_sjw_01 (1,180,563,613bp)
Total Length (>=50,000bp): pbjelly_sjw_01 (57,741,906bp)
N50: redundans_sjw_03 (17,679bp)

Jupyter Notebook (GitHub): 20180116_swoose_oly_assembly_comparisons_quast.ipynb


Genome Assembly – Olympia Oyster Illumina & PacBio Using PB Jelly w/BGI Scaffold Assembly

After another attempt to fix PB Jelly, I ran it again.

We’ll see how it goes this time…

Re-ran this using the BGI Illumina scaffolds FASTA.

Here’s a brief rundown of how this was run:

See the Jupyter Notebook for full details of run (see Results section below).


Output folder: http://owl.fish.washington.edu/Athaliana/20171130_oly_pbjelly/

Output FASTA file: http://owl.fish.washington.edu/Athaliana/20171130_oly_pbjelly/jelly.out.fasta

Quast assessment of output FASTA:

Assembly jelly.out
# contigs (>= 0 bp) 696946
# contigs (>= 1000 bp) 159429
# contigs (>= 5000 bp) 68750
# contigs (>= 10000 bp) 35320
# contigs (>= 25000 bp) 7048
# contigs (>= 50000 bp) 894
Total length (>= 0 bp) 1253001795
Total length (>= 1000 bp) 1140787867
Total length (>= 5000 bp) 932263178
Total length (>= 10000 bp) 691523275
Total length (>= 25000 bp) 261425921
Total length (>= 50000 bp) 57741906
# contigs 213264
Largest contig 194507
Total length 1180563613
GC (%) 36.57
N50 12433
N75 5983
L50 26241
L75 60202
# N’s per 100 kbp 6580.58

Have added this assembly to our Olympia oyster genome assemblies table.

This took an insanely long time to complete (nearly six weeks)!!! After some internet searching, I’ve found a pontential solution to this and have initiated another PB Jelly run to see if it will run faster. Regardless, it’ll be interesting to see how the results compare from two independent runs of PB Jelly.

Jupyter Notebook (GitHub): 20171130_emu_pbjelly.ipynb