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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How to quantifiy of specific genes from shotgun metagenome?

I have googled a "lot", couldn't find any specific answer to the question. So, I am here seeking for your guidance. My question is similar to this. I have several metagenome (n=30). But for ...
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Trinity assembly from many samples

When you combine samples for de-novo transcriptome assembly with Trinity, do you suggest limiting the number of reads for each sample? I had read one of Matthew MacManes' papers awhile back suggesting ...
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Genome annotation

I have helped a lab sequence a mitochondrial genome. I used then MITOS to annotate the genome (warning them that I did it just for curiosity as I am not experienced). They submitted the sequence and ...
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where to find sample contig data

Where or How can I find contigs? I am trying to learn Bioinformatics and I want to make a reference-based gene search. I also want to align contigs with a given reference sequence. From NCBI other ...
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Denovo, Stacks: Getting an “ambiguous redirect” error

I tried running the following command ...
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Genome QC + Assembly Pipeline semantics

I’m trying to create a pipeline for genome assembly. How best can I “redirect/pipe” from existing fasta files (or files in general) to other steps of the pipeline? I was thinking of going from the SRA ...
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Quast duplication ratio and mismatches percent

When analyzing Quast results it seems that it doesn't calculate mismatches and indels in a useful way if the "Duplication ratio" is over 1. For example, that's what I get for an assembly ...
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Gold standard benchmark

This page is claimed to contain a gold standard benchmark for viral genome assembly. https://github.com/cbg-ethz/5-virus-mix The claim is here: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5411778/ &...
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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 ...
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Which one is a more convenient assembly?

I have developed a software for de novo genome assembly. Its performance varies gradually according to how much data you employ. At initial stages it often produces contigs that look like that when ...
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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 <...
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Is it possible to filter contaminated reads for raw PacBio sequences (not HiFi reads) before assembly?

De novo genome assembly for non-model organisms face the issue of bacterial contamination. For assembled contigs with mostly bacterial-like sequences (based on BLAST search), the entire contig can be ...
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Is there a simple command for outputting a tab delimited columns?

I am working on a fasta file and am writing my command in nano within command-line and executing using python, also within a command line. My objective is to get my command to provide me with a tab ...
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creating a tab delimited file

I am working on a project using a fasta file. I am writing my command in nano within command-line and executing using python, also within my command-line. I would like my command to provide me with a ...
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Is it possible to convert BAM file from one genome assembly to the other?

I Have multiple BAM files that are referenced to UCSC genome assembly GRCh37/hg19 that are read in different time frames. Now, I am planning a different studies that require assembling all the data ...
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Contamination on genome assembly

I had a question for the community. I have a genome of a new species that has been sequenced via 150pb Illumina paired-end. To verify the quality of the assembly I used the ...
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55 views

How to find all WGS assemblies accessions of a species

Some background Similar to the OP of https://www.biostars.org/p/377840/, I would like to programmatically BLAST a sequence to a local database of all WGS assemblies. Since this isn't feasible for the ...
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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 ...
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155 views

Difference between paired-end, mate-pair and long read

I writing here because I have some questions for you. I wondered what the essential differences were between paired-end, ...
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PacBio long-reads impact in transcriptome de novo assembly?

We are strongly interested in assembly a good transcriptome of reference for a non-model organism and build a local database. We have sequenced the same individual with Illumina (150 millions of pair-...
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Genome assembly of SRR12196449 with SPAdes

I am trying to assemble the run SRR12196449 with SPAdes. The description of their project is: This project expected to standardize a method for amplification and ...
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How can I get or create a reference genome for Bacteria?

I am a computer engineer and nowadays trying to grasp some concepts of Bioinformatics particularly, reference genomes and genomic variants. My aim is to find the effect of sequence features on variant ...
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RCSB API: limited returned result

Is there a limit of query results on RCSB API? Interestingly, no matter how to adjust my query criteria, only 10 assemblies are returned. Here is an example query json: (truncated from a longer query ...
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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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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/...
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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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Gap-fill assembly with PacBio reads

I would like to gap-fill (or correct) a mammalian-sized assembly for which we have BACs that have been sequenced with PacBio CLR data. I have seen there are pbm22/gcpp tools available for correcting ...
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217 views

Difference between genome assembly and genome sequence alignment to a reference to find structural variants

I'm trying to determine what the difference and benefits of genome assembly and genome sequence alignments are when trying to identify structural variants or transposons in populations. I've been ...
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How to fragment genomes into non-overlapping sequences of differing sizes?

I have bacterial chromosomes/plasmids that I have downloaded off refseq in a multi-fasta that I would like to fragment into non-overlapping fragments of between 1 kb and 15 kb. I have tried googling ...
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Bacterial DNA at the tail of transcriptome reads. What does that mean?

I am assembling a transcriptome obtained from the Internet. The transcriptome was extracted from a human cancer tissue that had been previously grafted into a mouse. I have detected that many ...
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Comparing gene abundances between metagenomes

My workflow until now: Find fragments of a marker gene in unassembled metagenomes > download and assemble metagenomes > recover the gene neighborhood / gene set of interest Right now I have a ...
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Can SBOL encode DNA Assembly linkers?

Where in an SBOL file could you specify the linkers that would be placed as prefixes / suffixes between parts for assembly? Lets say you have a final construct of your design and want to assemble the ...
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Decontaminating RNA seqs for de novo transcriptome assembly and annotation of novel eukaryotes

I have raw paired-end RNA-seq reads for two novel eukaryotic species. Some background: the reads represent a copepod (arthropod) species each. The mRNA for each read set was obtained by extracting ...
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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 ...
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“megahit: command not found” after correct installation with miniconda

I want to use MEGAHIT (git: https://github.com/voutcn/megahit) to assemble metagenome shotgun sequencing reads (illumina). I install the package with the command <...
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Methods to predict one connected structure from two known separate structures

Currently, I am facing such a question: how to predict one connected protein structures from two separate known structures? It should be different from the protein-protein docking method, which is ...
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Assemble reads for a specific gene

I have a lot of unassembled sequencing data and I want to build phylogeny for some genes from these data. I can retrieved the sequene by mapping reads to a reference sequence but if the two species ...
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After KEGG and GO analysis, how to make tables+phylogenetic trees

hope everyone is ok. I used Trinity to do a de novo transcriptome assembly, then blastp/blastx and then used Blast2GO software to do KEGG and GO analysis. So i got some txt files with header : for GO ...
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What is the meaning of these misaligned reads in a sequencing run?

I am analyzing some SARS-CoV-2 sequencing runs abd often find read alignments like the one in the image. ...
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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 ...
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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 ...
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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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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 ...
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Optimum parameters for genome assembly via canu

I have been trying to assemble my genome via canu. Canu gave me about 200 contigs using default parameters. My genomesize is ~9Mbp. Can you recommend some parameters I can tweak to decrease the ...
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Tools for comparing/visualizing FASTAs?

I have two FASTAs/assemblies of the same species, but the bases are somewhat different. I would like to explore this. What tools/methods exist to compare two FASTAs and see the difference in ...
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Can I get longer contigs by changing MEGAHIT settings?

My current settings are megahit -r input.fq --num-cpu-threads 32 --min-contig-len 300 --presets meta-large -o output. I picked the 'presets meta-large' because I am ...
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What assembler is appropriate for High-Fidelity PacBio reads

What assembler is appropriate for High-Fidelity PacBio reads? For example, canu is good for high-error PacBio reads. But what algorithm to use for HiFi reads? Would it be OK to use canu without the ...
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mapping and de novo assembly of plant without reference genome

I'm studying on a plant that has no reference genome and only has one scaffold assembly and one gff3 annotation file. Can I create an index with the same assembly and gff3 in STAR and do the mapping? ...
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197 views

nanopore - where to retrieve information from the basecaller used

Where can I find information about the basecaller used in a specific nanopore run (we have a Gridion machine)? I know already that we have Guppy v. 3.0.3, which I ...
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Finding simple sequence from reads with significant overlap

I wrote a "script" to pull out reads from a huge fastq file in an iterative manner, by finding homology to the previous sequence. It should be relatively easy to overlap them and assemble ...