BOL: Related items

Common steps for reads mapping !

BioStar — Thu, 09 Mar 2023 02:48:02 -0600

Mapping reads to a reference genome is an essential step in many types of genomic analysis, such as variant calling and gene expression analysis. Here are some general steps to follow for mapping reads to a genome:

Choose a read mapper: There are many read mappers available, such as BWA, Bowtie, and HISAT2. Choose a mapper that is appropriate for your type of data and research question.
Index the reference genome: Before mapping reads, the reference genome needs to be indexed. This involves creating an index of the genome sequence that allows the mapper to quickly find matches to the reads. Most mappers have their own indexing tools.
Prepare the read data: The reads should be in a format that is compatible with the mapper. Most mappers accept FASTQ or BAM files. Depending on the quality of the data, it may need to be filtered or trimmed before mapping.
Run the mapper: The mapper is run with the command-line interface or using a graphical user interface. The specific command depends on the mapper being used, but typically involves specifying the input data, reference genome, and output file format.
Evaluate the mapping results: After the mapping is complete, the results should be evaluated. This includes assessing the quality of the mapping, such as the mapping rate, the number of mapped reads, and the mapping quality score.
Post-processing: Depending on the analysis being performed, post-processing of the mapped reads may be necessary. This can include filtering reads based on quality, removing duplicate reads, and calling variants.

Overall, mapping reads to a reference genome is a complex process that requires careful consideration of the type of data, the research question, and the specific mapper being used.

SOAP2 : Short Oligonucleotide Analysis Package 2

Poonam Mahapatra — Wed, 23 May 2018 10:09:22 -0500

SOAPaligner/soap2 is a member of the SOAP (Short Oligonucleotide Analysis Package). It is an updated version of SOAP software for short oligonucleotide alignment. The new program features in super fast and accurate alignment for huge amounts of short reads generated by Illumina/Solexa Genome Analyzer. Compared to soap v1, it is one order of magnitude faster. It require only 2 minutes aligning one million single-end reads onto the human reference genome. Another remarkable improvement of SOAPaligner is that it now supports a wide range of the read length. SOAPaligner benefitted in time and space efficiency by a revolution in the basic data structures and algorithms used.The core algorithms and the indexing data structures (2way-BWT) are developed by the algorithms research group of the Department of Computer Science, the University of Hong Kong (T.W. Lam, Alan Tam, Simon Wong, Edward Wu and S.M. Yiu).

Address of the bookmark: http://soap.genomics.org.cn/soapaligner.html

vt: a variant tool set that discovers short variants from Next Generation Sequencing data.

Jit — Tue, 28 Jan 2020 03:44:43 -0600

vt is a variant tool set that discovers short variants from Next Generation Sequencing data.

https://genome.sph.umich.edu/wiki/Vt

https://github.com/atks/vt

Address of the bookmark: https://genome.sph.umich.edu/wiki/Vt

Added video feature in BOL

Jitendra Narayan — Tue, 13 Aug 2013 17:42:16 -0500

Just in: Added video features in BOL, now you can watch and share your favourite bioinformatics video tutorials.

Share your favourite video tutorial or lectures on BOL at http://bioinformaticsonline.com/videolist/all . You can also add video in you groups.

Note: Other than bioinformatics video material/tutorial will be deleted without any prior warning.

Ruby and BioRuby Tutorials

Jitendra Narayan — Mon, 26 Aug 2013 17:18:28 -0500

Collections of Ruby and BioRuby learning materials.

BioRuby paper link : http://bioinformatics.oxfordjournals.org/content/26/20/2617.abstract

Address of the bookmark: http://www.codeschool.com/paths/ruby

Next generation sequencing(NGS) books

Abhimanyu Singh — Fri, 30 May 2014 04:48:04 -0500

Employing different technologies, the purpose of NGS platform is to decode the identity or modification on the nucleotides. NGS platforms evolve quickly and capture the main stream.

This bookmark is created to provide NGS online books links.

Address of the bookmark: http://en.wikibooks.org/wiki/Next_Generation_Sequencing_%28NGS%29/Print_version

R for Microsoft Excel

Jitendra Narayan — Wed, 18 Feb 2015 00:43:27 -0600

If you currently use a spreadsheet like Microsoft Excel for data analysis, you might be interested in taking a look at this tutorial on how to transition from Excel to R by Tony Ojeda. The tutorial explains how to use R functions in place of Excel formulas, including tools like =AVERAGE and =VLOOKUP. For the most part, it uses modern R packages to keep the R code clear and concise.

You'll likely still be using Excel as a data source, though, so you'll also want to check out this guide to importing data from Excel to R from MilanoR.

Reference http://www.r-bloggers.com/an-r-tutorial-for-microsoft-excel-users/

A guide for complete R beginners :- Installing R packages

Archana Malhotra — Tue, 24 Feb 2015 20:23:34 -0600

Part of the reason R has become so popular is the vast array of packages available at the cran and bioconductor repositories. In the last few years, the number of packages has grown exponentially!

This is a short post giving steps on how to actually install R packages. Let’s suppose you want to install the ggplot2 package. Well nothing could be easier. We just fire up an R shell and type:
> install.packages("ggplot2")

In theory the package should just install, however:

if you are using Linux and don’t have root access, this command won’t work.
you will be asked to select your local mirror, i.e. which server should you use to download the package.

Installing packages without root access

First, you need to designate a directory where you will store the downloaded packages. On my machine, I use the directory /data/Rpackages/ After creating a package directory, to install a package we use the command:
> install.packages("ggplot2", lib="/data/Rpackages/") > library(ggplot2, lib.loc="/data/Rpackages/")

It’s a bit of a pain having to type /data/Rpackages/ all the time. To avoid this burden, we create a file .Renviron in our home area, and add the line R_LIBS=/data/Rpackages/ to it. This means that whenever you start R, the directory /data/Rpackages/ is added to the list of places to look for R packages and so:

> install.packages("ggplot2") > library(ggplot2)

just works!

Setting the repository

Every time you install a R package, you are asked which repository R should use. To set the repository and avoid having to specify this at every package install, simply:

create a file .Rprofile in your home area.
Add the following piece of code to it:

cat(".Rprofile: Setting UK repositoryn") r = getOption("repos") # hard code the UK repo for CRAN r["CRAN"] = "http://cran.uk.r-project.org" options(repos = r) rm(r)

I found this tip in a stackoverflow answer .

Visual machine learning !!!

Jitendra Narayan — Wed, 29 Jul 2015 04:29:13 -0500

In machine learning, computers apply statistical learning techniques to automatically identify patterns in data. These techniques can be used to make highly accurate predictions.

More at http://www.r2d3.us/visual-intro-to-machine-learning-part-1/

Address of the bookmark: http://www.r2d3.us/visual-intro-to-machine-learning-part-1/

Painless package development for R

Abhi — Tue, 03 May 2016 05:31:06 -0500

Devtools makes package development a breeze: it works with R’s existing conventions for code structure, adding efficient tools to support the cycle of package development. With devtools, developing a package becomes so easy that it will be your default layout whenever you’re writing a significant amount of code.

Before you get started be sure to check out:

Address of the bookmark: https://www.rstudio.com/products/rpackages/devtools/