BOL: Related items

KisSplice

Jit — Tue, 16 Aug 2016 08:34:19 -0500

KisSplice is a software that enables to analyse RNA-seq data with or without a reference genome. It is an exact local transcriptome assembler that allows to identify SNPs, indels and alternative splicing events. It can deal with an arbitrary number of biological conditions, and will quantify each variant in each condition. It has been tested on Illumina datasets of up to 1G reads. Its memory consumption is around 5Gb for 100M reads.

KisSplice is not a full-length transcriptome assembler. This means that it will output the variable regions of the transcripts, not reconstruct them entirely.

KisSplice comes as a workflow, with several possible post-treatments meant to facilitate the analysis of the results. The choice of the post-treatment depends on the availability of a reference genome/transcriptome and on the need to perform a differential analysis, as summarised in the following table.

Address of the bookmark: http://kissplice.prabi.fr/

LSC: Improving PacBio Long Read Accuracy by Short Read Alignment

Abhimanyu Singh — Thu, 06 Sep 2018 16:27:35 -0500

Added Command line argument support.
Multi-stage execution modes.
Support for parallelization. Now execution proceeds in batches of long reads the size of which can be set by --long_read_batch_size N.
Better compressed intermediate files.
Added utilities folder.
Added support for multiple short read files.
Removed use of configuration file.

Address of the bookmark: https://www.healthcare.uiowa.edu/labs/au/LSC/

Cheatsheet for Linux !!

Jit — Wed, 22 Jun 2016 07:55:06 -0500

Linux Commands Cheat Sheet

    File System

    ls — list items in current directory

    ls -l — list items in current directory and show in long format to see perimissions, size, an modification date

    ls -a — list all items in current directory, including hidden files

    ls -F — list all items in current directory and show directories with a slash and executables with a star

    ls dir — list all items in directory dir

    cd dir — change directory to dir

    cd .. — go up one directory

    cd / — go to the root directory

    cd ~ — go to to your home directory

    cd - — go to the last directory you were just in

    pwd — show present working directory

    mkdir dir — make directory dir

    rm file — remove file

    rm -r dir — remove directory dir recursively

    cp file1 file2 — copy file1 to file2

    cp -r dir1 dir2 — copy directory dir1 to dir2 recursively

    mv file1 file2 — move (rename) file1 to file2

    ln -s file link — create symbolic link to file

    touch file — create or update file

    cat file — output the contents of file

    less file — view file with page navigation

    head file — output the first 10 lines of file

    tail file — output the last 10 lines of file

    tail -f file — output the contents of file as it grows, starting with the last 10 lines

    vim file — edit file

    alias name 'command' — create an alias for a command
    System

    shutdown — shut down machine

    reboot — restart machine

    date — show the current date and time

    whoami — who you are logged in as

    finger user — display information about user

    man command — show the manual for command

    df — show disk usage

    du — show directory space usage

    free — show memory and swap usage

    whereis app — show possible locations of app

    which app — show which app will be run by default
    Process Management

    ps — display your currently active processes

    top — display all running processes

    kill pid — kill process id pid

    kill -9 pid — force kill process id pid
    Permissions

    ls -l — list items in current directory and show permissions

    chmod ugo file — change permissions of file to ugo - u is the user's permissions, g is the group's permissions, and o is everyone else's permissions. The values of u, g, and o can be any number between 0 and 7.

    7 — full permissions

    6 — read and write only

    5 — read and execute only

    4 — read only

    3 — write and execute only

    2 — write only

    1 — execute only

    0 — no permissions

    chmod 600 file — you can read and write - good for files

    chmod 700 file — you can read, write, and execute - good for scripts

    chmod 644 file — you can read and write, and everyone else can only read - good for web pages

    chmod 755 file — you can read, write, and execute, and everyone else can read and execute - good for programs that you want to share
    Networking

    wget file — download a file

    curl file — download a file

    scp user@host:file dir — secure copy a file from remote server to the dir directory on your machine

    scp file user@host:dir — secure copy a file from your machine to the dir directory on a remote server

    scp -r user@host:dir dir — secure copy the directory dir from remote server to the directory dir on your machine

    ssh user@host — connect to host as user

    ssh -p port user@host — connect to host on port as user

    ssh-copy-id user@host — add your key to host for user to enable a keyed or passwordless login

    ping host — ping host and output results

    whois domain — get information for domain

    dig domain — get DNS information for domain

    dig -x host — reverse lookup host

    lsof -i tcp:1337 — list all processes running on port 1337
    Searching

    grep pattern files — search for pattern in files

    grep -r pattern dir — search recursively for pattern in dir

    grep -rn pattern dir — search recursively for pattern in dir and show the line number found

    grep -r pattern dir --include='*.ext — search recursively for pattern in dir and only search in files with .ext extension

    command | grep pattern — search for pattern in the output of command

    find file — find all instances of file in real system

    locate file — find all instances of file using indexed database built from the updatedb command. Much faster than find

    sed -i 's/day/night/g' file — find all occurrences of day in a file and replace them with night - s means substitude and g means global - sed also supports regular expressions
    Compression

    tar cf file.tar files — create a tar named file.tar containing files

    tar xf file.tar — extract the files from file.tar

    tar czf file.tar.gz files — create a tar with Gzip compression

    tar xzf file.tar.gz — extract a tar using Gzip

    gzip file — compresses file and renames it to file.gz

    gzip -d file.gz — decompresses file.gz back to file
    Shortcuts

    ctrl+a — move cursor to beginning of line

    ctrl+f — move cursor to end of line

    alt+f — move cursor forward 1 word

    alt+b — move cursor backward 1 word

KAST

Neel — Wed, 23 Feb 2022 08:28:36 -0600

Perform Alignment-free k-tuple frequency comparisons from sequences. This can be in the form of two input files (e.g. a reference and a query) or a single file for pairwise comparisons to be made.

Address of the bookmark: https://github.com/martinjvickers/KAST

A5-miseq

Jit — Thu, 18 Aug 2016 04:05:23 -0500

_A5-miseq_ is a pipeline for assembling DNA sequence data generated on the Illumina sequencing platform. This README will take you through the steps necessary for running _A5-miseq_.

Point to note:

There are many situations where A5-miseq is not the right tool for the job. In order to produce accurate results, A5-miseq requires Illumina data with certain characteristics. A5-miseq will likely not work well with Illumina reads shorter than around 80nt, or reads where the base qualities are low in all or most reads before 60nt. A5-miseq assumes it is assembling homozygous haploid genomes. Use a different assembler for metagenomes and heterozygous diploid or polyploid organisms. Use a different assembler if a tool like FastQC reports your data quality is dubious. You have been warned! Datasets consisting solely of unpaired reads are not currently supported.

Address of the bookmark: https://sourceforge.net/projects/ngopt/

Basics of BLAST Programs !

BioStar — Fri, 26 Jul 2024 06:04:26 -0500

The Basic Local Alignment Search Tool (BLAST) is a powerful bioinformatics program used to compare an input sequence (such as DNA, RNA, or protein sequences) against a database of sequences to find regions of similarity. Developed by the National Center for Biotechnology Information (NCBI), BLAST is widely used for identifying species, finding functional and evolutionary relationships between sequences, and predicting the function of novel sequences.

Key Features of BLAST:
1. Sequence Comparison: BLAST searches for local alignments between the query sequence and sequences in a database. It identifies regions of similarity, which can help infer functional and evolutionary relationships.

2. Speed and Efficiency: BLAST uses heuristic algorithms, making it faster than exhaustive search methods, suitable for large-scale database searches.

3. Versatility: There are several versions of BLAST for different types of sequence comparisons:
- blastn: Compares a nucleotide query sequence against a nucleotide sequence database.
- blastp: Compares a protein query sequence against a protein sequence database.
- blastx: Compares a nucleotide query sequence translated in all reading frames against a protein sequence database.
- tblastn: Compares a protein query sequence against a nucleotide sequence database translated in all reading frames.
- tblastx: Compares the six-frame translations of a nucleotide query sequence against the six-frame translations of a nucleotide sequence database.

4. Scoring and E-value: BLAST results are scored based on the quality and length of the alignments. The E-value (expect value) indicates the number of alignments one can expect to find by chance, with lower E-values representing more significant matches.

5. Output Formats: BLAST provides results in various formats, including plain text, HTML, XML, and JSON, making it adaptable for different types of analyses and integrations with other tools.

Applications of BLAST:
- Genomic Research: Identifying genes, understanding genetic diversity, and mapping genome sequences.
- Protein Function Prediction: Inferring the function of unknown proteins by comparing them to known protein sequences.
- Evolutionary Studies: Exploring evolutionary relationships between organisms by comparing their genetic material.
- Medical Research: Identifying pathogens, understanding disease mechanisms, and developing treatments by comparing sequences of interest.

Overall, BLAST is an essential tool in bioinformatics, offering a reliable and efficient way to analyze and interpret biological sequence data.

Kraken: ultrafast metagenomic sequence classification using exact alignments

Jit — Mon, 27 Jun 2016 11:01:44 -0500

Kraken is an ultrafast and highly accurate program for assigning taxonomic labels to metagenomic DNA sequences. Previous programs designed for this task have been relatively slow and computationally expensive, forcing researchers to use faster abundance estimation programs, which only classify small subsets of metagenomic data. Using exact alignment of k-mers, Kraken achieves classification accuracy comparable to the fastest BLAST program. In its fastest mode, Kraken classifies 100 base pair reads at a rate of over 4.1 million reads per minute, 909 times faster than Megablast and 11 times faster than the abundance estimation program MetaPhlAn. Kraken is available at http://ccb.jhu.edu/software/kraken/.

Krona

https://sourceforge.net/p/krona/home/krona/

Address of the bookmark: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4053813/

Quota synteny alignment

Jit — Mon, 31 Jul 2017 04:11:57 -0500

Typically in comparative genomics, we can identify anchors, chain them into syntenic blocks and interpret these blocks as derived from a common descent. However, when comparing two genomes undergone ancient genome duplications (plant genomes in particular), we have large number of blocks that are not orthologous, but are paralogous. This has forced us sometimes to use ad-hoc rules to screen these blocks. So the question is: given the expected depth (quota) along both x- and y-axis, select a subset of the anchors with maximized total score.

Address of the bookmark: https://github.com/tanghaibao/quota-alignment

Machine Learning !!!

Gudiya Pal — Fri, 01 Jul 2016 12:57:12 -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.

Keep scrolling. Using a data set about homes, we will create a machine learning model to distinguish homes in New York from homes in San Francisco.

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

Mugsy: multiple whole genome alignment tool

Jit — Fri, 08 Dec 2017 17:41:14 -0600

Mugsy is a multiple whole genome aligner. Mugsy uses Nucmer for pairwise alignment, a custom graph based segmentation procedure for identifying collinear regions, and the segment-based progressive multiple alignment strategy from Seqan::TCoffee. Mugsy accepts draft genomes in the form of multi-FASTA files and does not require a reference genome.

To cite Mugsy, use:

Angiuoli SV and Salzberg SL. Mugsy: Fast multiple alignment of closely related whole genomes.Bioinformatics 2011 27(3):334-4

Address of the bookmark: http://mugsy.sourceforge.net/