Questions tagged [assembly]

Process of creating the original sequence from the read sequences that it generated during a sequencing experiment. Can refer to genome assembly, in which case the original sequence is a genome, or transcripts assembly, in which case the original sequences are RNA transcripts.

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1answer
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wtdbg2: practical implications of k-mer fsize and psize choice

I am using wtdbg2 2.3 to assemble a human genome (sequenced on PromethION from a cell line). I filtered out reads with low average quality, and now I am trying to determine the parameters that will ...
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0answers
50 views

What is the current state-of-the-art in assembling hybrid transcriptomes?

We are considering attempting de novo assembly of a species transcriptomes (i.e. without a reference genome) using the combined NGS outputs of Iso-seq and Illumina. One example I saw (Li et al 2017),...
3
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2answers
99 views

Merge / Reconciliate several de novo transcriptome assemblies with different kmers

I am building a De Novo transcriptome reference assembly for an eukaryotic organism for which I have a genome. I've created several assemblies with rnaSpades using different kmer sizes (19 to 69 with ...
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0answers
1k views

SPAdes error during assembly

I try to perform a hybrid assembly using Unicycler. Unicycler use SPAdes to assembly the illumina sequences, and the program crashes while in SPAdes. The spades.log file says something about an ...
3
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0answers
183 views

How to submit a canu job on LSF high-performance computing cluster farm?

I am currently running canu on an LSF Linux server using the following script called assemble.sh: ...
2
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0answers
146 views

Platanus-allee phasing fail: Error(13): Error, SolveDBG exception!

I am using Platanus-allee 2.2.2 for heterozygous genome (~500mb) assembly with Illumina short reads and PacBio reads input data. I have the file contigs.fa from short reads but phasing step with ...
2
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1answer
39 views

polishing assembled genome to QV50 value

I am trying to assemble some genomes from pacbio reads using HGAP3 followed by quiver polishing. However, even after multiple rounds of quiver polishing, I cannot attain quality value 50 (QV50) for a ...
2
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0answers
41 views

Calculating alignment/mapping time

I am trying to assemble a plant genome using AWS resources using velvet. Plant genome is huge (> 10 times human genome) and coverage is around 30 x. We are planning for de novo assembly with Velvet (...
2
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2answers
173 views

Is there any value in scaffolding the output contigs of MEGAHIT assembler given a metagenomic dataset?

As far as I understood, for most assembly programs, the scaffolding step takes into consideration paired-end information in order to get from contigs (contiguous sequences) to scaffolds (longer ...
1
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0answers
14 views

Repeat analysis on eukaryotic assemblies

I have a hundred insect genomes and I'm looking for repeated regions along these assemblies. First of all, I thought of using <...
1
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1answer
49 views

Interpreting contig alignments to a reference genome

I have applied two de novo genome assembly tools to data from the run SRR12707453, corresponding to a phage (I downloaded the data and have no relation with the authors of the study). Using rnaSPAdes ...
0
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1answer
16 views

Denovo, Stacks: Getting an “ambiguous redirect” error

I tried running the following command ...
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0answers
39 views

How to filter a genome assembly consistsing of a large number of contigs?

I did some de novo genome assemblies with Illumina PE data using SPAdes, whereas most of them consisting of a large number of contigs(>1000). I have several questions below. Do we need to filter ...
0
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0answers
36 views

Which of the Transcriptome assembly method is best for identifying novel lncRNAs?

I'm working with human samples and I'm trying to identify novel lncRNAs from tumor samples of Prostate cancer. I'm using reference based transcriptome assembly with ...
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0answers
21 views

Filtering out nonarthropod sequences using Blobtools2

I am using Blobtools2 and am working my way through the sample dataset that they provide before using my own. The filtering tutorial I am following is --> https://blobtoolkit.genomehubs.org/...
0
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0answers
56 views

Resources to learn genome assembly workflow for small genomes (like viruses)

I have sequencing data of a few samples of a DNA genome virus. I'd like to learn de novo assembly of the ...
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0answers
58 views

Gffcompare issue: 0 reference transcripts loaded

I am trying to use gffcompare to compare my assembled transcriptome to a reference gtf that contains information about small open reading frames (sORFs). The reference gtf was obtained by processing ...
0
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1answer
46 views

Will using smaller kmers help get larger contigs? If not, then what?

I've been using MEGAHIT to assemble metagenomes, with particular focus on specific genomic areas. Sometimes all I get is gene fragments or pathway fragments (eg. if I know that genes A, B, C, D and E ...
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0answers
44 views

How to obtain the extended unaligned bases of the read in reference based genome assembly?

I did illumina read mapping based on a particular gene sequence (reference sequence) using the following command, ...
0
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0answers
60 views

Canu failed with 'didn't find any mers?'

I have installed canu using conda in an environment containing Python 3 on a Mac OS X. I checked that canu is properly installed by pulling out the help and it works. I launched a canu assembly job by ...