Questions tagged [metagenome]

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2answers
38 views

Software for taxonomic assignment?

I have a couple of hundred bacterial sequences of 2-30 genes of interest each, recovered from metagenomics. None of them encode rRNA. Normally I'd just BLAST the one gene I already know to be reliable ...
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2answers
53 views

How identifiable are human omics data and how to mitigate their identifying features?

Say a database were to store human omics datasets. The human subjects are known and the sample size is rather small in size initially (n=500). The database contains genomics, transcriptomics, ...
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0answers
37 views

Kraken2 > OTU format > Phyloseq

A collaborator has passed me over Kraken2 outputs *.report and *.kraken, from a metatranscriptomic sequencing experiment conducted on the minION. I would like to use this data in phyloseq, however, I ...
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1answer
25 views

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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1answer
30 views

Is it conflicting: significant difference according to Wald test but not in PERMANOVA and ANOSIM to compare species abundances of metagenomic samples?

If there is no significant difference between two groups of metagenomic samples according to "Multivariate differential abundance tests" for example PERMANOVA and ANOSIM, does it makes sense to use "...
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0answers
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Alternatives to phrap for merging contigs with overlapping ends?

I have bins from metagenomes generated with metabat2 (https://bitbucket.org/berkeleylab/metabat/src) which are predicted as viral by MARVEL (https://github.com/laboratoriobioinformatica/MARVEL). ...
2
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2answers
60 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 ...
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2answers
30 views

Software for microbial profiling from 16S rRNA gene sequence

I have hundreds of GBs metagenomic 16S rRNA gene sequence data. I want to do microbiome composition profiling (with relative abundance) from the data. Also after that, I will do functional profiling (...
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1answer
39 views

NCBI SRA database sample: control vs test

I was trying to download some data from NCBI SRA (SRA059451). There are 27 samples available for SRA059451. But i am unable to understand which samples are 'control' and 'test' samples. Please help me ...
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1answer
32 views

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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0answers
37 views

How to calculate coverage depth of genes in an annotated sequence?

I have a metagenomic dataset across multiple samples that has been grouped and binned (we did this due to poor sequence quallity). I have annotated the bins and now want to calculate the abundance of ...
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0answers
16 views

Is there a way to extract reads assigned to a particular taxonomic node from SRA data?

I've noticed that SRR submissions have an 'Analysis' section, where one can see what organisms are enriched in the sample; there is even a great graphic display that uses Krona to highlight what ...
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1answer
33 views

Metagenomic shotgun data with internal control

For 24 human stool samples I have metagenomic shotgun reads from an Illumina platform. The reads were filtered and mapped against a bacterial species library and specific maps to species were kept and ...
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3answers
113 views

Python module for fetching NCBI id for a list of species

I have a list of scientific names of species. Is there a python module that can fetch NCBI taxonomy IDs?
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0answers
52 views

How to apply RDP, Greengenes and other special taxonomies in Krona?

I used Kraken 2 to classify my 16S metagenomic data using both RDP and Greengenes database. As these are special databases the taxonomic ids assigned do not match with the NCBI taxonomic ids. I found ...
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0answers
24 views

Illumina 16S amplicon sequencing of healthy human cohort

I am looking for a 16S amplicon (ideally V3-V4) dataset from Illumina paired-end sequencing, which is similar to the healthy human cohort of the human microbiome project. I am primarily interested in ...
0
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0answers
23 views

How to build ML tree among OTUs and 16s sequence

I have OTUs sequence generated from 16s V4 clean reads, and want to build maximum likelhood tree with selcted taxonomy 16s refseq from Sliva database. ...
5
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1answer
84 views

Is there a way to assemble contigs starting from a specific sequence?

My work involves searching for marker genes/fragments in metagenomic databases (like the Sequence Read Archive). Once I find these sequences, I would like to know more about the neighboring genomic ...
2
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1answer
64 views

API/website for blasting peptide sequence against database of all plant proteomes

I would like to blast a peptide sequence against all available plant proteome databases, i.e. a blastp metaproteome analysis. What tools are available? Which ...
3
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1answer
60 views

How to query the Human Microbiome Project (HMP) to find all subjects with both 16s and WGS workups?

I am looking for a query to run on the HMP database that will return all subjects who have had BOTH 16s and whole genomes sequence (WGS) workups. I am currently using this query... ...
5
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1answer
123 views

Viral Metagenomics

I am analyzing viral metagenomics data (Illumina Miseq) for the first time. I have used Ray for de novo viral genome assembly before but I haven't done metagenomics analysis before. I know that there ...
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2answers
81 views

What are Approximate Read Counts (Library Sizes) and Lengths (Insert Sizes) for Next-Generation DNA Sequencers?

I am performing a simulation study and am curious about the parameters of my simulated metagenome. What are the library and insert sizes of some of the most "used" sequencers. Mainly, I am ...
4
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1answer
113 views

Using large databases with BLAT

I'm a computer scientist working with biologists at a small school that doesn't have dedicated bioinformatics staff. I apologize if I use incorrect terminology since I have limited bioinformatics ...
4
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2answers
269 views

Transform traditional blast output to `--outfmt 6`

I have run a blastx of metagenomic databases (raw illumina reads) using the nr database. Unfortunately, I forgot to add the --outfmt 6 argument to the code and got ...
3
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0answers
217 views

Microbial diversity analysis using whole-genome metagenomic data

I have data, obtained from a single metagenomic DNA sample, that consists of two MiSeq FASTQ files (R1 and R2) that I merged using PEAR. Now I want to estimate the abundances of the bacteria taxa to ...
11
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5answers
209 views

How do I efficiently perform a metagenome screen of “all” species?

I’ve got an RNA-seq dataset with a large proportion of environmental RNA “contamination”. BLASTing random reads reveals that much of the data comes from bacterial, plant and viral RNA. My target ...
1
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2answers
127 views

Workflow of metabarcoding analysis

For a diet analysis of an insect-eating animal, all species in a sample shall be identified. For this a sequencing of the metagenomic sample was done, where the COI/COX region was used as a barcode ...
8
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3answers
320 views

Pooling data in metagenome assembly

I have 12 human gut microbiome WGS Nextseq reads (151 bp paired end). What will be an effective strategy to assemble a metagenome? Let us say I have already filtered the fastq for quality, adapter ...
7
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2answers
7k views

How to use Python to count k-mers?

I have some FASTQ sequence files and a FASTA file for some regions I'm interested in. I would like: Build an index for the FASTA file Use the index to count number of k-mers occurred in my sequence ...
6
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1answer
54 views

What's the scaling for HOMER metagenes?

I'm trying to use HOMER to make a metagene profile over gene bodies using a bedgraph file I've generated. The problem is that every time I do, I get really weird scaling on the y-axis. I should be ...
1
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3answers
220 views

Accidental mapping of eukaryotic reads in a metagenomic dataset

This is a question from /u/wipeyourmit on reddit. The original post can be found here. If I have a metagenomic dataset that contains reads from both eukaryotes and prokaryotes and then I annotate ...
5
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1answer
201 views

Rapid metagenomics classifiers on long read data [closed]

I recently used the minION (Nanopore, 9.4 flow cell, RAD001 kit) to generate a metagenome out of environmental samples. Passed reads weren't brilliant (196, average 1,594bp lenght), but working with ...