BOL: Related items

Computer simulation of genetic mechanism !!

Jit — Sun, 13 Mar 2016 09:29:56 -0500

Computer simulation is the discipline of designing a model of an actual or theoretical physical/biological system, executing the model on a digital computer, and analyzing the execution output. Simulation embodies the principle of ``learning by doing'' --- to learn about the system we must first build a model of some sort and then operate the model. The use of simulation is an activity that is as natural as a child who role plays. Children understand the world around them by simulating (with toys and figurines) most of their interactions with other people, animals and objects. As adults, we lose some of this childlike behavior but recapture it later on through computer simulation. To understand reality and all of its complexity, we must build artificial objects and dynamically act out roles with them. Computer simulation is the electronic equivalent of this type of role playing and it serves to drive synthetic environments and virtual worlds. Within the overall task of simulation, there are three primary sub-fields: model design, model execution and model analysis

Simulation models have become important tools in Bioinformatics studies. There are many reasons for this, but we emphasize three of the more important:

(1) they enable exploration of hypotheses, and as such, have become invaluable means to guide research;

(2) they are unique approaches to integrate (in the literal term of the word) biological knowledge, in the form of experimental results; and

(3) they enable connecting biology with other fields of study ranging from physiology to genomics;

This blog, and this software list, is intended to guide the potential user of simulation models.
It is not, in any way, meant to be comprehensive on the very diverse simulation tools that already exist, but focuses on mechanistic, dynamic models. Similarly, it is not meant to provide any coverage of the breadth of applications; however, for interested readers, we provide references to use as a possible starting point.

Simulation models are meant to answer questions which scientists have in a dynamic, quantitative, and often, a pictorial way. Much of the bioinformatics research and its applications, in particular, involve a large number of components, actors, and factors. Assembling these in a coherent framework may seem a daunting task, especially for beginners, and can lead to confusion, even for experienced scientists, especially if the objectives of such an exercise are not well defined. Followings are the list of tools bioinformatician may use to analyze and provide answers to complex biological mechanisms and related problems.

Software Resource	Brief Description and Homepage
Aladyn	Tools to investigate how demographic parameters, populations genetics and abiotic conditions affect the rate of adaptation http://www.katja-schiffers.eu/research.html
ALF	A Simulation Framework for Genome Evolution http://www.cbrg.ethz.ch/alf
ART	ART is a set of simulation tools to generate synthetic next-generation sequencing data by mimicking real sequencing process with empirical error models or quality profiles. http://www.niehs.nih.gov/research/resources/software/biostatistics/art/
BAMSurgeon	Methods for realistic simulation of mutations in real data. https://github.com/adamewing/bamsurgeon
Bayesian Serial SimCoal	Bayesian Serial SimCoal, (BayeSSC) is a modification of SIMCOAL 1.0, a program written by Laurent Excoffier, John Novembre, and Stefan Schneider. http://www.stanford.edu/group/hadlylab/ssc/index.html
BaySICS	An integral platform with a graphical interface for statistical inference based on approximate Bayesian computation. https://sites.google.com/site/baysicsabc/
BEERS	BEERS was designed to benchmark RNA-Seq alignment algorithms and also algorithms that aim to reconstruct different isoforms and alternate splicing from RNA-Seq data http://cbil.upenn.edu/beers/
BOTTLENECK	Bottleneck is a program for detecting recent effective population size reductions from allele data frequencies http://www.ensam.inra.fr/urlb/bottleneck/bottleneck.html
BottleSim	BottleSim is a computer simulation program for simulating the process of population bottlenecks http://chkuo.name/software/bottlesim.html
CASS	Protein Sequence Simulation https://liberles.cst.temple.edu/software/cass/index.html
CDPOP	CDPOP is a landscape genetics tool for simulating the emergence of spatial genetic structure in populations resulting from specified landscape processes governing organism movement behavior. http://cel.dbs.umt.edu/cdpop
Classical Genetics Simulator	Web-based simulation software http://www.cgslab.com/
CoaSim	CoaSim is a tool for simulating the coalescent process with recombination and geneconversion under various demographic models. http://users-birc.au.dk/mailund/coasim/index.html
cosi	The cosi package is written in C and is available as a tar file. http://www.broadinstitute.org/~sfs/cosi/
CS-PSeq-Gen	A program to simulate the evolution of protein sequences under the constraints of the information of a particular reconstructed phylogeny http://bioserv.rpbs.univ-paris-diderot.fr/software/cs-pseq-gen/
DAWG	An application designed to simulate the evolution of recombinant DNA sequences in continuous time http://scit.us/projects/dawg
Easypop	EASYPOP is an individual based model intended to simulate datasets under a very broad range of conditions http://www.unil.ch/dee/en/home/menuinst/softwares--dataset/softwares/easypop.html
EggLib	EggLib is a C++/Python library and program package for evolutionary genetics and genomics. http://egglib.sourceforge.net/
EpiSIM	EpiSIM: simulation of multiple epistasis, linkage disequilibrium patterns and haplotype blocks for genome-wide interaction analysis https://sourceforge.net/projects/episimsimulator/files/
EvolSimulator	A simulation test bed for hypotheses of genome evolution http://acb.qfab.org/acb/evolsim/
EvolveAGene	A realistic coding sequence simulation program that separates mutation from selection and allows the user to set selection conditions http://bellinghamresearchinstitute.com/software/index.html
fastsimcoal	A continuous-‐time coalescent simulator of genomic diversity under arbitrarily complex evolutionary scenarios http://cmpg.unibe.ch/software/fastsimcoal/
FastSLINK	Simulation of Marker and Phenotype Data in Pedigrees https://watson.hgen.pitt.edu/
FFPopSim	C++/Python library for population genetics. http://webdav.tuebingen.mpg.de/ffpopsim/
FLUX SIMULATOR	The Flux Simulator aims at providing a deterministic in silico reproduction of the experimental pipelines for RNA-Seq, employing a minimal set of parameters. http://sammeth.net/confluence/display/sim/home
forqs	Forward-in-time simulation of Recombination, Quantitative Traits, and Selection https://bitbucket.org/dkessner/forqs
ForSim	ForSim: A Forward Evolutionary Computer Simulation http://anth.la.psu.edu/research/weiss-lab/research/research
ForwSim	The program given below is based on the algorithm described in Padhukasahasram et al. 2008 to simulate genetic drift in a standard Wright-Fisher process. http://badri-populationgeneticsimulators.blogspot.com/
FPG	Forward Population Genetic simulation https://bio.cst.temple.edu/~hey/software/software.htm#fpg
FREGENE	FREGENE is a C++ program that simulates sequence-like data over large genomic regions in large diploid populations. http://www.ebi.ac.uk/projects/bargen
FIGG	FIGG is a genome simulation tool that uses known or theorized variation frequency, per a given fragment size and grouped by GC content across a genome to model new genomes in FASTA format while tracking applied mutations for use in analysis http://insilicogenome.sourceforge.net/
fwdpp	A C++ template library for implementing efficient forward simulations. http://molpopgen.github.io/fwdpp/
GAMETES	Genetic Architecture Model Emulator for Testing and Evaluating Software: Simulates complex SNP models with pure, strict epistatic interactions with n-loci. http://sourceforge.net/projects/gametes/?source=navbar
GASP	Genometric Analysis Simulation Program. A software tool for testing and investigating methods in statistical genetics by generating samples of family data based on user specified models. http://research.nhgri.nih.gov/gasp/
GCTA	Genome-wide Complex Trait Analysis http://www.complextraitgenomics.com/software/gcta/download.html
GemSIM	Next generation sequencing read simulator http://sourceforge.net/projects/gemsim/
GeneArtisan	Simulation of Markers in Case-Control Study Designs http://www.rannala.org/?page_id=241
GENOME	A rapid coalescent-based whole genome simulator http://www.sph.umich.edu/csg/liang/genome/
GenomePop2	GenomePop2 is a specialization of the program GenomePop just to manage SNPs under more flexible and useful settings. If you need models with more than 2 alleles please use the GenomePop program version. https://ritchielab.psu.edu/research/research-areas/statistical-genetics-and-gen-epi/methods/genomesimla
GenomeSimla	GenomeSIMLA is currently under development- however, we have a beta release that we are asking to be tested http://chgr.mc.vanderbilt.edu/genomesimla/
GENS2	Simulates interactions among two genetic and one environmental factor and also allows for epistatic interactions. https://sourceforge.net/projects/gensim/
GWAsimulator	A rapid whole genome simulation program http://biostat.mc.vanderbilt.edu/wiki/main/gwasimulator
HAP-SAMPLE	An association simulator for candidate regions or genome scans http://www.hapsample.org/
HAPGEN	A simulator for the simulation of case control datasets at SNP markers https://mathgen.stats.ox.ac.uk/genetics_software/hapgen/hapgen2.html
HapSim	A simulation tool for generating haplotype data with pre-specified allele frequencies and LD coefficients http://cran.r-project.org/web/packages/hapsim/index.html
HAPSIMU	A program that simulates heterogeneous populations with various known and controllable structures under the continuous migration model or the discrete model http://l.web.umkc.edu/liujian/
IBDsim	IBDSim is a computer package for the simulation of genotypic data under general isolation by distance models. http://raphael.leblois.free.fr/
indel-Seq-Gen	A biological sequence simulation program that simulates highly divergent DNA sequences and protein superfamilies http://bioinfolab.unl.edu/~cstrope/isg/
Indelible	A powerful and flexible simulator of biological evolution http://abacus.gene.ucl.ac.uk/software/indelible/
invertFREGENE	InvertFREGENE is a forward-in-time simulator of inversions in population genetic data http://www.ebi.ac.uk/projects/bargen/
kernalPop	A spatially explicit population genetic simulation engine http://cran.r-project.org/src/contrib/archive/kernelpop/
MaCS	Markovian Coalescent Simulator http://www-hsc.usc.edu/~garykche/
Marlin	Marlin provides a user-friendly interface for performing forward-in-time population genetic simulations. http://www.patrickmeirmans.com/software/marlin.html
Mason	A package for the simulation of nucleotide data. http://www.seqan.de/projects/mason/
mbs	modifying Hudson's ms software to generate samples of DNA sequences with a biallelic site under selection http://www.sendou.soken.ac.jp/esb/innan/innanlab/software.html
Mendel's Accountant	Mendel's Accountant (MENDEL) is an advanced numerical simulation program for modeling genetic change over time and was developed collaboratively by Sanford, Baumgardner, Brewer, Gibson and ReMine http://mendelsaccount.sourceforge.net/
MetaPopGen	Simulates genetics in large size metapopulations https://sites.google.com/site/marcoandrello/metapopgen
MetaSim	A tool to generate collections of synthetic reads that reflect the diverse taxonomical composition of typical metagenome data sets http://ab.inf.uni-tuebingen.de/software/metasim/
mlcoalsim	Multilocus Coalescent Simulations http://code.google.com/p/mlcoalsim-v1/
ms	The purpose of this program is to allow one to investigate the statistical properties of such samples, to evaluate estimators or statistical tests, and generally to aid in the interpretation of polymorphism data sets. http://home.uchicago.edu/~rhudson1/source/mksamples.html
msHOT	The purpose of this program is to allow one to investigate the statistical properties of such samples, to evaluate estimators or statistical tests, and generally to aid in the interpretation of polymorphism data sets. http://home.uchicago.edu/~rhudson1/
msms	A coalescent Simlation tool with selection. http://www.mabs.at/ewing/msms/index.shtml
MySSP	A program for the simulation of DNA sequence evolution across a phylogenetic tree http://www.rosenberglab.net/software.html
Nemo	A forward-time, individual-based, genetically explicit, and stochastic simulation program designed to study the evolution of genetic markers, life history traits, and phenotypic traits in a flexible (meta-)population framework. http://nemo2.sourceforge.net/
NetRecodon	Coalescent simulation of coding DNA sequences with recombination (inter and intracodon), migration and demography http://code.google.com/p/netrecodon/
OncoSimulR	BioConductor package for Forward Genetic Simulation of Cancer Progresion with Epistasis https://github.com/rdiaz02/oncosimul
PEDAGOG	Software for simulating eco-evolutionary population dynamics https://bcrc.bio.umass.edu/pedigreesoftware/node/5
phenosim	A tool to add phenotypes to simulated genotypes http://evoplant.uni-hohenheim.de/doku.php?id=software:software
PhyloSim	An R package for the Monte Carlo simulation of sequence evolution http://www.ebi.ac.uk/goldman-srv/phylosim/
pIRS	Profile-based Illumina pair-end reads simulator https://code.google.com/p/pirs/
ProteinEvolver	Simulation of protein evolution along phylogenies under structure-based substitution models http://code.google.com/p/proteinevolver/
QMSim	QTL and Marker Simulator http://www.aps.uoguelph.ca/~msargol/qmsim/
quantiNEMO	An individual-based program for the analysis of quantitative traits with explicit genetic architecture potentially under selection in a structured population http://www2.unil.ch/popgen/softwares/quantinemo/
RECOAL	Simulates new haplotype data from a reference population of haplotypes. ftp://popgen.usc.edu/
Recodon	Coalescent simulation of coding DNA sequences with recombination, migration and demography http://code.google.com/p/recodon/
rlsim	A package for simulating RNA-seq library preparation with parameter estimation http://bit.ly/rlsim-git
Rmetasim	Rmetasim is a front-end for the metasim engine that is implemented as a package that runs in the statistical computing environment R http://cran.r-project.org/web/packages/rmetasim/index.html
RNA Seq Simulator	RSS takes SAM alignment files from RNA-Seq data and simulates over dispersed, multiple replica, differential, non-stranded RNA-Seq datasets. http://useq.sourceforge.net/cmdlnmenus.html#rnaseqsimulator
Rose	Random model of sequence evolution http://bibiserv.techfak.uni-bielefeld.de/rose/
scrm	A coalescent simulator optimized for long sequences and large samples. https://scrm.github.io/
SelSim	SelSim is a program for Monte Carlo simulation of DNA polymorphism data for a recom- bining region within which a single bi-allelic site has experienced natural selection http://www.well.ox.ac.uk/~spencer/selsim/
Seq-Gen	An application for the Monte Carlo simulation of molecular sequence evolution along phylogenetic trees. http://tree.bio.ed.ac.uk/software/seqgen/
SEQPower	Statistical power analysis for sequence-based association studies http://bioinformatics.org/spower/
SeqSIMLA	SeqSIMLA can simulate sequence data with user-specified disease and quantitative trait models. Family or unrelated case-control data can be simulated. http://seqsimla.sourceforge.net/
Serial NetEvolve	A flexible utility for generating serially-sampled sequences along a tree or recombinant network http://biorg.cis.fiu.edu/sne/
SFS_CODE	SFS_CODE can perform forward population genetic simulations under a general Wright-Fisher model with arbitrary migration, demographic, selective, and mutational effects. http://sfscode.sourceforge.net/sfs_code/index/index.html
SIBSIM	Quantitative phenotype simulation in extended pedigrees http://sourceforge.net/projects/sibsim/
SimAdapt	A spatially explicit, individual-based, forward-time, landscape-genetic simulation model combined with a landscape cellular automaton. https://www.openabm.org/model/3137
SIMCOAL2	A coalescent program for the simulation of complex recombination patterns over large genomic regions under various demographic models http://cmpg.unibe.ch/software/simcoal2/
SimCopy	An R package simulating the evolution of copy number profiles along a tree. http://bit.ly/simcopy
SIMLA	SIMLA is a SIMuLAtion program that generates data sets of families for use in Linkage and Association studies. http://dmpi.duke.edu/simla-simulation-software-version-32
SimPed	A Simulation Program to Generate Haplotype and Genotype Data for Pedigree Structures http://bioinformatics.org/simped/
Simprot	A program to simulate protein evolution by substitution, insertion and deletion http://www.uhnresearch.ca/labs/tillier/software.htm#3
SimRare	Rare variant simulation and analysis tool http://code.google.com/p/simrare/
simuGWAS	A forward-time simulator that simulates realistic samples for genome-wide association studies. http://simupop.sourceforge.net/cookbook/simugwas
simuPOP	simuPOP is a general-purpose individual-based forward-time population genetics simulation environment. http://simupop.sourceforge.net/
SISSI	A software tool to generate data of related sequences along a given phylogeny, taking into account user defined system of neighbourhoods and instantaneous rate matrices. http://www.cibiv.at/software/sissi/
SMARTPOP	Simulating Mating Alliance as a Reproductive Tactic for Populations http://smartpop.sourceforge.net/
SNPsim	Coalescent simulation of hotspot recombination http://code.google.com/p/phylosoftware/
SPIP	SPIP simulates the transmission of genes from parents to offspring in a population having demographic structure defined by the user http://swfsc.noaa.gov/textblock.aspx?division=fed&id=3434
Splatche	Spatial and Temporal Coalescences in Heterogeneous Environment http://www.splatche.com/
srv	Simulator of Rare Varaints (srv) is a simulator for the simulation of the introduction and evolution of (rare) genetic variants. http://simupop.sourceforge.net/cookbook/simurarevariants
SUP	SLINK/FastSLINK utility program http://mlemire.freeshell.org/software.html
TreesimJ	A flexible, forward-time population genetic simulator http://code.google.com/p/treesimj/
Variant Simulation Tools	A simulation tool for post-GWAS genetic epidemiological studies using whole-genome or whole-exome next-gen sequencing data, with an emphasis on user-friendliness and reproducibility. http://varianttools.sourceforge.net/simulation/homepage
Vortex	VORTEX is an individual-based simulation model for population viability analysis (PVA). http://www.vortex9.org/vortex.html
Wessim	Whole Exome Sequencing SIMulator http://sak042.github.io/wessim/

Andi

Jit — Fri, 13 May 2016 05:16:35 -0500

This is the andi program for estimating the evolutionary distance between closely related genomes. These distances can be used to rapidly infer phylogenies for big sets of genomes. Because andi does not compute full alignments, it is so efficient that it scales even up to thousands of bacterial genomes.

This readme covers all necessary instructions for the impatient to get andi up and running. For extensive instructions please consult the manual.

More at https://github.com/evolbioinf/andi/

Address of the bookmark: http://bioinformatics.oxfordjournals.org/content/early/2015/01/13/bioinformatics.btu815.full

BBMap/BBTools package: Multipurpose tool designed for converting reads or other nucleotide data between different formats.

Jit — Mon, 13 Jun 2016 05:47:21 -0500

Reformatis a member of the BBMap/BBTools package. It is a multipurpose tool designed for converting reads or other nucleotide data between different formats. It supports, and can inter-convert:

fastq
fasta
fasta+qual
sam
scarf (an old Illumina format)
bam (if samtools is installed)
gzip
zip
ascii-33 (sanger)
ascii-64 (old Illumina)
paired files
interleaved files

It is multithreaded and can process data at over 500 megabytes per second, and can accept streams from standard in and write to standard out, allowing it to be easily dropped into the middle of a pipeline for format conversion. Reformat autodetects formats based on file extensions and content, making it very easy to use; and the autodetection can be overridden, allowing flexibility for people who don't like to follow naming conventions, or out-of-spec fastq files with qualities values like -17 or 120.

The program has been gradually expanded, and can now perform various other functions. None of these will break pairing, if the input is paired.

Quality trimming (either or both ends)
Quality filtering
Fixed-length trimming
Generation of histograms (base composition, quality, etc)
Subsampling (to a fraction of input reads, or an exact number of reads or bases)
Changing fasta line-wrapping length
Reverse-complementing (all reads or only read 2)
Adding /1 and /2 suffix to read names
GC-content filtering
Length-filtering
Testing for corrupted interleaved files

Reformat is compatible with any platform that supports Java 1.7 or higher. It also has a bash shellscript for simpler invocation. Typical usage examples:

Reformat fastq into fasta:
reformat.sh in=x.fq out=y.fa

Interleave paired reads:
reformat.sh in1=x1.fq in2=x2.fq out=y.fq

Note - you can actually use a shortcut if paired read files have the same name with a 1 and a 2. This is equivalent to the above command:
reformat.sh in=x#.fq out=y.fq

De-interleave reads:
reformat.sh in=x.fq out1=y1.fq out2=y2.fq

Verify that interleaving appears correct, assuming Illumina namimg conventions:
reformat.sh in=x.fq vint

Convert ASCII-33 to ASCII-64:
reformat.sh in=x.fq out=y.fq qin=33 qout=64

Quality-trim paired reads to Q10 on the left and right ends and discard reads shorter than 50bp after trimming:
reformat.sh in1=x1.fq in2=x2.fq out1=y1.fq out2=y2.fq outsingle=singletons.fq qtrim=rl trimq=10 minlength=50

Subsample 10% of the first 20000 pairs in an interleaved file:
reformat.sh in=x.fq out=y.fq reads=20000 samplerate=0.1 int=t
(in this case "int=t" overrides interleaving autodetection, to ensure reads are treated as pairs)

Pipe in a gzipped sam file and pipe out fasta:
reformat.sh in=stdin.sam.gz out=stdout.fa

Reverse-complement reads:
reformat.sh in=x.fq out=y.fq rcomp

For reformatting a file with very long sequences, Reformat will need more memory; just add the additional flag "-Xmx2g". For example, to change the line-wrapping length on the human genome (which has individual sequences over 200Mbp long) to 70 characters:
reformat.sh -Xmx2g in=HG19.fa.gz out=HG19_wrapped.fa.gz fastawrap=70

For additional functions, please run the shellscript with no arguments, or just read it with a text editor. If you have any questions, please post them in this thread.

For people using a non-bash terminal, you may need to type "bash reformat.sh" instead of just "reformat.sh".
For users of Windows or other platforms that do not support bash shellscripts, replace "reformat.sh" with "java -ea -Xmx200m /path/to/bbmap/current/ jgi.ReformatReads"
for example,
java -ea -Xmx200m C:\bbmap\current\ jgi.ReformatReads in=x.fq out=y.fa

Reformat can be downloaded with BBTools here:
https://sourceforge.net/projects/bbmap/

LoRMA: a tool for correcting sequencing errors in long reads such those produced by Pacific Biosciences sequencing machines

Jit — Wed, 15 Jun 2016 17:18:36 -0500

LoRMA is a tool for correcting sequencing errors in long reads such those produced by Pacific Biosciences sequencing machines.

Publication:

L. Salmela, R. Walve, E. Rivals, and E. Ukkonen: Accurate selfcorrection of errors in long reads using de Bruijn graphs. Accepted to RECOMB-Seq 2016.

Download:

Address of the bookmark: https://www.cs.helsinki.fi/u/lmsalmel/LoRMA/

SAM flags

Poonam Mahapatra — Wed, 29 Jun 2016 15:38:15 -0500

Decoding SAM flags

This utility makes it easy to identify what are the properties of a read based on its SAM flag value, or conversely, to find what the SAM Flag value would be for a given combination of properties.

To decode a given SAM flag value, just enter the number in the field below. The encoded properties will be listed under Summary below, to the right.

Address of the bookmark: https://broadinstitute.github.io/picard/explain-flags.html

Kaiju

Jit — Mon, 27 Jun 2016 11:23:04 -0500

Kaiju is a program for the taxonomic classification of metagenomic high-throughput sequencing reads. Each read is directly assigned to a taxon within the NCBI taxonomy by comparing it to a reference database containing microbial and viral protein sequences.

By default, Kaiju uses either the available complete genomes from NCBI RefSeq or the microbial subset of the non-redundant protein database nr used by NCBI BLAST, optionally also including fungi and microbial eukaryotes.

Kaiju translates reads into amino acid sequences, which are then searched in the database using a modified backward search on a memory-efficient implementation of the Burrows-Wheeler transform, which finds maximum exact matches (MEMs), optionally allowing mismatches in the protein alignment. The search can process up to millions of reads per minute using, for example, only 10 GB RAM with a protein database comprising 4821 microbial genomes. Kaiju can also be used for querying any other protein database without taxonomic classification, using either protein or nucleotide queries.

Kaiju is described in Menzel, P. et al. (2016) Fast and sensitive taxonomic classification for metagenomics with Kaiju. Nat. Commun. 7:11257 (open access).

Address of the bookmark: http://kaiju.binf.ku.dk/

Scarpa

Poonam Mahapatra — Wed, 13 Jul 2016 07:59:25 -0500

Scarpa is a stand-alone scaffolding tool for NGS data. It can be used together with virtually any genome assembler and any NGS read mapper that supports SAM format. Other features include support for multiple libraries and an option to estimate insert size distributions from data. Scarpa is available free of charge for academic and commercial use under the GNU General Public License (GPL).

See the user manual or the paper for more information about Scarpa. Click here for the supplementary material.

Address of the bookmark: http://compbio.cs.toronto.edu/hapsembler/scarpa.html

SPAdes hybrid genome assembly

Jit — Mon, 27 Nov 2017 08:05:40 -0600

When you have both Illumina and Nanopore data, then SPAdes remains a good option for hybrid assembly - SPAdes was used to produce the B fragilis assembly by Mick Watson’s group.

Again, running spades.py will show you the options:

spades.py

This produces:

SPAdes genome assembler v3.10.1

Usage: /usr/local/SPAdes-3.10.1-Linux/bin/spades.py [options] -o 

Basic options:
-o          directory to store all the resulting files (required)
--sc                    this flag is required for MDA (single-cell) data
--meta                  this flag is required for metagenomic sample data
--rna                   this flag is required for RNA-Seq data
--plasmid               runs plasmidSPAdes pipeline for plasmid detection
--iontorrent            this flag is required for IonTorrent data
--test                  runs SPAdes on toy dataset
-h/--help               prints this usage message
-v/--version            prints version

Input data:
--12          file with interlaced forward and reverse paired-end reads
-1            file with forward paired-end reads
-2            file with reverse paired-end reads
-s            file with unpaired reads
--pe<#>-12            file with interlaced reads for paired-end library number <#> (<#> = 1,2,..,9)
--pe<#>-1             file with forward reads for paired-end library number <#> (<#> = 1,2,..,9)
--pe<#>-2             file with reverse reads for paired-end library number <#> (<#> = 1,2,..,9)
--pe<#>-s             file with unpaired reads for paired-end library number <#> (<#> = 1,2,..,9)
--pe<#>-    orientation of reads for paired-end library number <#> (<#> = 1,2,..,9;  = fr, rf, ff)
--s<#>                file with unpaired reads for single reads library number <#> (<#> = 1,2,..,9)
--mp<#>-12            file with interlaced reads for mate-pair library number <#> (<#> = 1,2,..,9)
--mp<#>-1             file with forward reads for mate-pair library number <#> (<#> = 1,2,..,9)
--mp<#>-2             file with reverse reads for mate-pair library number <#> (<#> = 1,2,..,9)
--mp<#>-s             file with unpaired reads for mate-pair library number <#> (<#> = 1,2,..,9)
--mp<#>-    orientation of reads for mate-pair library number <#> (<#> = 1,2,..,9;  = fr, rf, ff)
--hqmp<#>-12          file with interlaced reads for high-quality mate-pair library number <#> (<#> = 1,2,..,9)
--hqmp<#>-1           file with forward reads for high-quality mate-pair library number <#> (<#> = 1,2,..,9)
--hqmp<#>-2           file with reverse reads for high-quality mate-pair library number <#> (<#> = 1,2,..,9)
--hqmp<#>-s           file with unpaired reads for high-quality mate-pair library number <#> (<#> = 1,2,..,9)
--hqmp<#>-  orientation of reads for high-quality mate-pair library number <#> (<#> = 1,2,..,9;  = fr, rf, ff)
--nxmate<#>-1         file with forward reads for Lucigen NxMate library number <#> (<#> = 1,2,..,9)
--nxmate<#>-2         file with reverse reads for Lucigen NxMate library number <#> (<#> = 1,2,..,9)
--sanger              file with Sanger reads
--pacbio              file with PacBio reads
--nanopore            file with Nanopore reads
--tslr        file with TSLR-contigs
--trusted-contigs             file with trusted contigs
--untrusted-contigs           file with untrusted contigs

Pipeline options:
--only-error-correction runs only read error correction (without assembling)
--only-assembler        runs only assembling (without read error correction)
--careful               tries to reduce number of mismatches and short indels
--continue              continue run from the last available check-point
--restart-from      restart run with updated options and from the specified check-point ('ec', 'as', 'k', 'mc')
--disable-gzip-output   forces error correction not to compress the corrected reads
--disable-rr            disables repeat resolution stage of assembling

Advanced options:
--dataset             file with dataset description in YAML format
-t/--threads               number of threads
                                [default: 16]
-m/--memory                RAM limit for SPAdes in Gb (terminates if exceeded)
                                [default: 250]
--tmp-dir              directory for temporary files
                                [default: /tmp]
-k                 comma-separated list of k-mer sizes (must be odd and
                                less than 128) [default: 'auto']
--cov-cutoff             coverage cutoff value (a positive float number, or 'auto', or 'off') [default: 'off']
--phred-offset  <33 or 64>      PHRED quality offset in the input reads (33 or 64)
                                [default: auto-detect]

As you can see this is also a “pipeline” of tools that can be switched on or off. SPAdes takes quite a long time, so for the purposes of this practical, something like this may suffice:

spades.py -t 4 \
          -m 32 \
          -k 31,51,71 \
          --only-assembler \
          -1 miseq.1.fastq -2 miseq.2.fastq \
          --nanopore minion.fastq \
          -o hybrid_assembly

In turn, these parameters mean

use 4 threads
max memory is 32Gb
use 3 kmer values to build the de bruijn graph(s) - 31, 51 and 71
only run the assembler, not the correction algorithm (for speed)
read 1 and read 2 of the MiSeq data
the nanopore data
put the output in folder “hybrid_assembly”

String graph based genome assembly software and tools !

Rahul Nayak — Tue, 19 Dec 2017 17:17:38 -0600

In graph theory, a string graph is an intersection graph of curves in the plane; each curve is called a "string". String graphs were first proposed by E. W. Myers in a 2005 publication. In recent Genome Research paper describing an innovative approach for assembling large genomes from NGS data caught our attention for several reasons. i) it give different "string graph" prospective of long lasting genome assembly problem ii) the paper is coauthored by Jared Simpson, the developer of ABySS assembler and Richard Durbin. iii) Simpson-Durbin algorithm is that it does not rely on de Bruijn graphs, and instead employs a different graph construction approach called ‘string graph’.

Following are the genome assembly tools based on string graph:

1.SGA (String Graph Assembler) https://github.com/jts/sga

Assembles large genomes from high coverage short read data. SGA is designed as a modular set of programs, which are used to form an assembly pipeline. SGA implements a set of assembly algorithms based on the FM-index. As the FM-index is a compressed data structure, the algorithms are very memory efficient. The SGA assembly has three distinct phases. The first phase corrects base calling errors in the reads. The second phase assembles contigs from the corrected reads. The third phase uses paired end and/or mate pair data to build scaffolds from the contigs. The output of this software is a PDF report that allows the properties of the genome and data quality to be visually explored. By providing more information to the user at the start of an assembly project, this software will help increase awareness of the factors that make a given assembly easy or difficult, assist in the selection of software and parameters and help to troubleshoot an assembly if it runs into problems.

2. SAGE: String-overlap Assembly of GEnomes https://github.com/lucian-ilie/SAGE2

SAGE, for de novo genome assembly. As opposed to most assemblers, which are de Bruijn graph based, SAGE uses the string-overlap graph. SAGE builds upon great existing work on string-overlap graph and maximum likelihood assembly, bringing an important number of new ideas, such as the efficient computation of the transitive reduction of the string overlap graph, the use of (generalized) edge multiplicity statistics for more accurate estimation of read copy counts, and the improved use of mate pairs and min-cost flow for supporting edge merging. The assemblies produced by SAGE for several short and medium-size genomes compared favourably with those of existing leading assemblers.

3. FSG: Fast String Graph

The new integrated assembler has been assessed on a standard benchmark, showing that fast string graph (FSG) is significantly faster than SGA while maintaining a moderate use of main memory, and showing practical advantages in running FSG on multiple threads. Moreover, we have studied the effect of coverage rates on the running times.

4. BASE https://github.com/dhlbh/BASE

It enhances the classic seed-extension approach by indexing the reads efficiently to generate adaptive seeds that have high probability to appear uniquely in the genome. Such seeds form the basis for BASE to build extension trees and then to use reverse validation to remove the branches based on read coverage and paired-end information, resulting in high-quality consensus sequences of reads sharing the seeds. Such consensus sequences are then extended to contigs. BASE is a practically efficient tool for constructing contig, with significant improvement in quality for long NGS reads. It is relatively easy to extend BASE to include scaffolding.

5. Fermi https://github.com/lh3/fermi/

Fermi is a de novo assembler with a particular focus on assembling Illumina short sequence reads from a mammal-sized genome. In addition to the role of a typical assembler, fermi also aims to preserve heterozygotes which are often collapsed by other assemblers. Its ultimate goal is to find a minimal set of unitigs to represent all the information in raw reads.

If you want to learn about String Graph assembler, please read the following papers -

i) The Fragment Assembly String Graph - E. W. Myers

This paper describes the String Graph concept.

ii) Efficient construction of an assembly string graph using the FM-index - Jared T. Simpson and Richard Durbin

This earlier paper from Simpson and Durbin

iii) Efficient de novo assembly of large genomes using compressed data structures - Jared T. Simpson and Richard Durbin

AlignGraph: algorithm for secondary de novo genome assembly guided by closely related references

Manisha Mishra — Tue, 17 Apr 2018 16:21:20 -0500

AlignGraph is a software that extends and joins contigs or scaffolds by reassembling them with help provided by a reference genome of a closely related organism.

Using AlignGraph

AlignGraph --read1 reads_1.fa --read2 reads_2.fa --contig contigs.fa --genome genome.fa --distanceLow distanceLow --distanceHigh distancehigh --extendedContig extendedContigs.fa --remainingContig remainingContigs.fa [--kMer k --insertVariation insertVariation --coverage coverage --part p --fastMap --ratioCheck --iterativeMap --misassemblyRemoval --resume]

Address of the bookmark: https://github.com/baoe/AlignGraph