The Stack Overflow podcast is back! Listen to an interview with our new CEO.

Questions tagged [illumina]

The tag has no usage guidance.

Filter by
Sorted by
Tagged with
0
votes
0answers
23 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 ...
1
vote
1answer
27 views

Total read count of shotgun affected by few highly abundant sequences

I am building statistical models to analyse output from Illumina shotgun sequencing (HiSeq 4000) on stool samples (but RNA-seq data should behave similarily). The raw counts are a statistical sample ...
1
vote
1answer
70 views

How to demultiplex a mix of single-indexed and dual-indexed samples

The problem If I have a sample sheet that contains both single-indexed and dual-indexed samples, I can split it up into two sample sheets and then run bcl2fastq on each one. However, when doing this, ...
2
votes
0answers
67 views

What could cause differing counts of R1 and R2 in Paired End Sequencing (RNASEQ)

I recently finished mapping an RNAseq run using STAR2.3.0 and noticed the read1 and read2 counts are different, according to samtools flagstat. The map% is ~80% but the R1 R2 counts are: R1=...
4
votes
2answers
102 views

How to predict stop codons in Illumina reads?

I have Illumina MiSeq paired-end reads from 150bp amplicons mapped to my reference genome (> 1000X coverage). These reads have indels that may or may not induce frameshifts. If the indel induces a ...
3
votes
2answers
152 views

Is there a safe catch-all adapter sequence for trimming?

I would like to trim/mark adapters using trimmomatic or picard MarkIlluminaAdapters from a series of Illumina Paired-End read fastqs. The fastq files may have been done using different kits or ...
3
votes
3answers
96 views

Tools for quality trimming at 5 prime?

I'm looking for a tool that is capable to do quality trimming at 5' end and it is configurable. For example, I can choose the quality trheshold, the read length, etc. Any recommendations? I'm ...
4
votes
2answers
249 views

“Sequence Duplication Levels” module still fails after pre-processing Illumina data

I want to ask about why the sequence duplication levels are high after I trimmed by using Trimmomatic? I am using the following Trimmomatic operations: ...
4
votes
2answers
102 views

How to align output of grep --color=always? (To QC fasta/fastq files)

Grepping out short sequences from a fasta or fastq file is a really useful way to look at sequencing data. Using the option --color=always makes this even more ...
2
votes
1answer
511 views

Why are there more barcodes than GEMs in 10X chromium data?

Question: Why are there more barcodes than GEMs in 10X chromium data? Introduction I have several 10X genomics chromium libraries made with the de novo assembly/genome protocol. The 10X chromium ...
8
votes
3answers
1k views

What is the index fastq file (sample_I*.fastq.gz) generated when demultiplexing Illumina paired-end runs?

What is the index fastq file that comes with some Illumina sequencing datasets? (The samplename_I*.fastq.gz file.) For example, I recently received some 10X ...
5
votes
2answers
317 views

What is the correct way to map Hi-C data with bwa mem?

Library Prep I have a Hi-C library prepped using an enzyme that cuts at GATC, so it leaves GATCGATC as the junction sequences. ...
1
vote
1answer
49 views

How many reads do I need for hybrid assembly

I have Illumina and PacBio reads and I would like to use dbg2olc for hybrid assembly. Part of dbg2olc is SelectLongestReads which select reads that sum to ...
1
vote
1answer
27 views

Genotyping with Illumina HumanOmni1-Quad before whole genome sequencing

I read a paper about (whole genome sequencing analysis of 100 Southeast Asian Malays. It says "Prior to library preparation, each sample was genotyped on the Illumina HumanOmni1-Quad as an initial ...
3
votes
3answers
94 views

Relationship between sequencing lane and ngs dataset

I am fairly new to NGS data analysis and I am struggling to understand the exact relationship between a sequencing lane and an NGS dataset. I should add I don't work in the lab, I only do ...
3
votes
1answer
583 views

Why do NEBNext indexing primers have sequence between the p5 oligo and index?

In a previous post I asked Why do NEB adapters have non-complementary sequence? Since then, I realized that there is some other sequence in the p5 indexing primer, as well as in the p7 indexing ...
3
votes
1answer
96 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 ...
0
votes
1answer
146 views

Get gene names corresponding to CPG probes

I have downloaded KIRC Methylation data (450K) using TCGA toolbox. The beta values given are with reference to CPG probes. Is there any package or function in R through which I can get the gene names ...
1
vote
1answer
55 views

How to QC overamplified shotgun library?

I made some NEB ultra II whole-genome shotgun libraries with around ~200ng of template going into the indexing PCR step. The PCR was run for 13 cycles and I ended up having high library concentrations ...
6
votes
1answer
50 views

SNP located within a promoter region (pig)

I have a couple of SNP identifiers such as MARC0073381 or ALGA0066960. The corresponding platform is Illumina Porcine SNP60 BeadChip (WG-410). I want to know if these SNP are located within a ...
6
votes
2answers
36 views

Does the MAPQ=0 fraction of a BAM file depend on the insert sizes?

When doing Illumina 2x150bp sequencing of genomic DNA, and after aligning the reads to GRCh38, does the percentage of the non-N fraction of the human genome as MAPQ=0 depend on the insert sizes of the ...
3
votes
1answer
102 views

Scaffolding a genome with hybrid data

I am assembling a ~500MB genome, and have ~150x long reads and ~200x 150bp PE short reads, with a ~400bp insert size. I've done a lot of work with minimap+miniasm, and have what I think is a good set ...
1
vote
2answers
63 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 ...
-2
votes
1answer
38 views

Downloading CopyNumber450k package from Bioconductor

I am trying to download CopyNumber450k package in the R processor on my laptop in order to see if I could do a step of protocol for my research proffessor. I was unable to successfully download the ...
3
votes
1answer
188 views

genes with highest RPKM/FPKM for a human RNA-seq experiment?

Which genes/transcripts show up as having the highest RPKM/FPKM on a human RNA-seq experiment? Is it usually the same genes/transcripts? EDIT: mRNAs (e.g. poly-A RNA-seq preps) and not including ...
6
votes
1answer
143 views

checks for spike-in sequence controls

I would like to know what do people verify when designing/using spike-in controls, to be used in sequencing experiments (mainly Illumina). So far I came up with this list: Does it align only to a ...
4
votes
1answer
56 views

Analyzing Illumina Counts

I'm pretty new to all of this--forgive me if this is a simple question. When I download illumina counts from GEO (like the supplementary file in GSE89225). Can I do comparisons directly on that file?...
5
votes
2answers
232 views

GRCh38 centromeres mappability

Is the mappability of the centromeres in the GRCh38 genome reference similar to each other? As far as I can remember when GRCh38 came out, the sequence of the centromeres was determined by a ...
4
votes
3answers
176 views

what percentage of the human genome is MAPQ=0?

When doing Illumina 2x150bp sequencing of genomic DNA, and after aligning the reads to GRCh38, what percentage of the non-N fraction of the human genome is MAPQ=0? This is, what part corresponds to ...