BOL: Related items

PERGA: A Paired-End Read Guided De Novo Assembler for Extending Contigs Using SVM and Look Ahead Approach

Rahul Nayak — Tue, 05 Jun 2018 09:57:11 -0500

PERGA - Paired End Reads Guided Assembler PERGA is a novel sequence reads guided de novo assembly approach which adopts greedy-like prediction strategy for assembling reads to contigs and scaffolds. Instead of using single-end reads to construct contig, PERGA uses paired-end reads and different read overlap sizes from O ≥ Omax to Omin to resolve the gaps and branches. Moreover, by constructing a decision model using machine learning approach based on branch features, PERGA can determine the correct extension in 99.7% of cases. PERGA will try to extend the contigs by all feasible nucleotides and determine if these multiple extensions due to sequencing errors or repeats by using looking ahead technology, and it also try to separate the different repeats of nearby genomic regions to make the assembly result more longer and accurate. The simulated E.coli paired-end reads data are generated using GemSim (KE McElroy, F Luciani, T Thomas. Gemsim: General, Error-Model Based Simulator of Next-Generation Sequencing Data. BMC Genomics 2012, 13:74), with coverage 50x, 60x, 100x, read lengths 100-bp, and can be downloaded from https://github.com/zhuxiao/data_PERGA.

Address of the bookmark: https://github.com/hitbio/PERGA

RaGOO: Fast Reference-Guided Scaffolding of Genome Assembly Contigs

Jit — Sun, 27 Oct 2019 00:57:23 -0500

Alonge M, Soyk S, Ramakrishnan S, Wang X, Goodwin S, Sedlazeck FJ, Lippman ZB, Schatz MC: Fast and accurate reference-guided scaffolding of draft genomes. bioRxiv 2019.

RaGOO is a tool for coalescing genome assembly contigs into pseudochromosomes via minimap2 alignments to a closely related reference genome. The focus of this tool is on practicality and therefore has the following features:

Good performance. On a MacBook Pro using Arabidopsis data, pseudochromosome construction takes less than a minute and the whole pipeline with SV calling takes ~2 minutes.
Intact ordering and orienting of contigs.
Misassembly correction
GFF lift-over
Structural variant calling with and integrated version of Assemblytics
Confidence scores associated with the grouping, localization, and orientation for each contig.

Address of the bookmark: https://github.com/malonge/RaGOO

Bandage: interactive visualization of de novo genome assemblies

Shruti Paniwala — Mon, 04 Dec 2017 10:09:37 -0600

Bandage (a Bioinformatics Application for Navigating De novo Assembly Graphs Easily) is a tool for visualizing assembly graphs with connections. Users can zoom in to specific areas of the graph and interact with it by moving nodes, adding labels, changing colors and extracting sequences. BLAST searches can be performed within the Bandage graphical user interface and the hits are displayed as highlights in the graph. By displaying connections between contigs, Bandage presents new possibilities for analyzing de novo assemblies that are not possible through investigation of contigs alone.

Availability and implementation: Source code and binaries are freely available at https://github.com/rrwick/Bandage. Bandage is implemented in C++ and supported on Linux, OS X and Windows. A full feature list and screenshots are available at http://rrwick.github.io/Bandage.

Address of the bookmark: http://rrwick.github.io/Bandage/

Bioinformatician’s Pocket Reference !!

RAJESH DETROJA — Sun, 08 Jun 2014 09:56:58 -0500

It is amusing how brain of bioinformaticians work! Learning a new programming language for days feels so much of fun that making 5 minute discussion with neighbours (unless under special circumstances!) in our own mother-tongue. Today every bioinformatician keeps more than few languages and core IT toolkits on their plate. It has become mandatory to be able to mould different code snippets to build our own custom workflows, and thus keeping syntax at our fingertips has become essential.Although Google is best way to get syntax problem solved, it is not a bad idea to keep reference sheets is our smartphones or stick out some printed sheets on the back of your door, in the old fashion way!!

Address of the bookmark: http://infoplatter.wordpress.com/2014/04/06/bioinformaticians-pocket-reference/

Perl Special Vars Quick Reference

Abhimanyu Singh — Tue, 07 Feb 2017 05:08:47 -0600

`$_`	The default or implicit variable.
`@_`	Subroutine parameters.
`$a` `$b`	sort comparison routine variables.
`@ARGV`	The command-line args.
Regular Expressions
`$`	Regexp parenthetical capture holders.
`$&`	Last successful match (degrades performance).
`${^MATCH}`	Similar to `$&` without performance penalty. Requires /p modifier.
$`	Prematch for last successful match string (degrades performance).
`${^PREMATCH}`	Similar to $` without performance penalty. Requires `/p` modifier.
`$'`	Postmatch for last successful match string (degrades performance).
`${^POSTMATCH}`	Similar to `$'` without performance penalty. Requires `/p` modifier.
`$+`	Last paren match.
`$^N`	Last closed paren match (last submatch).
`@+`	Offsets of ends of successful submatches in scope.
`@-`	Offsets of starts of successful submatches in scope.
`%+`	Like `@+`, but for named submatches.
`%-`	Like `@-`, but for named submatches.
`$^R`	Last regexp (?{code}) result.
`${^RE_DEBUG_FLAGS}`	Current value of regexp debugging flags. See `use re 'debug';`
`${^RE_TRIE_MAXBUF}`	Control memory allocations for RE optimizations for large alternations.
Encoding
`${^ENCODING}`	The object reference to the Encode object, used to convert the source code to Unicode.
`${^OPEN}`	Internal use: \0 separated Input / Output layer information.
`${^UNICODE}`	Read-only Unicode settings.
`${^UTF8CACHE}`	State of the internal UTF-8 offset caching code.
`${^UTF8LOCALE}`	Indicates whether UTF8 locale was detected at startup.
IO and Separators
`$.`	Current line number (or record number) of most recent filehandle.
`$/`	Input record separator.
`$\|`	Output autoflush. 1=autoflush, 0=default. Applies to currently selected handle.
`$,`	Output field separator (lists)
`$\`	Output record separator.
`$"`	Output list separator. (interpolated lists)
`$;`	Subscript separator. (Use a real multidimensional array instead.)
Formats
`$%`	Page number for currently selected output channel.
`$=`	Current page length.
`$-`	Number of lines left on page.
`$~`	Format name.
`$^`	Name of top-of-page format.
`$:`	Format line break characters
`$^L`	Form feed (default "\f").
`$^A`	Format Accumulator
Status Reporting
`$?`	Child error. Status code of most recent system call or pipe.
`$!`	Operating System Error. (What just went 'bang'?)
`%!`	Error number hash
`$^E`	Extended Operating System Error (Extra error explanation).
`$@`	Eval error.
`${^CHILD_ERROR_NATIVE}`	Native status returned by the last pipe close, backtick (`` ) command, successful call to wait() or waitpid(), or from the system() operator.
ID's and Process Information
`$$`	Process ID
`$<`	Real user id of process.
`$>`	Effective user id of process.
`$(`	Real group id of process.
`$)`	Effective group id of process.
`$0`	Program name.
`$^O`	Operating System name.
Perl Status Info
`$]`	Old: Version and patch number of perl interpreter. Deprecated.
`$^C`	Current value of flag associated with -c switch.
`$^D`	Current value of debugging flags
`$^F`	Maximum system file descriptor.
`$^I`	Value of the -i (inplace edit) switch.
`$^M`	Emergency Memory pool.
`$^P`	Internal variable for debugging support.
`$^R`	Last regexp (?{code}) result.
`$^S`	Exceptions being caught. (eval)
`$^T`	Base time of program start.
`$^V`	Perl version.
`$^W`	Status of -w switch
`${^WARNING_BITS}`	Current set of warning checks enabled by `use warnings;`
`$^X`	Perl executable name.
`${^GLOBAL_PHASE}`	Current phase of the Perl interpreter.
`$^H`	Internal use only: Hook into Lexical Scoping.
`%^H`	Internaluse only: Useful to implement scoped pragmas.
`${^TAINT}`	Taint mode read-only flag.
`${^WIN32_SLOPPY_STAT}`	If true on Windows `stat()` won't try to open the file.
Command Line Args
`ARGV`	Filehandle iterates over files from command line (see also `<>`).
`$ARGV`	Name of current file when reading <>
`@ARGV`	List of command line args.
`ARGVOUT`	Output filehandle for -i switch
Miscellaneous
`@F`	Autosplit (-a mode) recipient.
`@INC`	List of library paths.
`%INC`	Keys are filenames, values are paths to modules included via `use, require,` or `do`.
`%ENV`	Hash containing current environment variables
`%SIG`	Signal handlers.
`$[`	Array and substr first element (Deprecated!).

See perlvar for detailed descriptions of each of these (and a few more) special variables.

kSNP3.0: SNP detection and phylogenetic analysis of genomes without genome alignment or reference genome

Jit — Fri, 08 Dec 2017 16:48:40 -0600

Sept. 20, 2017 Version 3.1 released. Major upgrade. Version 3.1 fixes the problems with SNP annotation that arose when NCBI discontinued use of GI numbers. Please read carefully the Preface (page 3) and the File of annotated genomes section (pages 9-10) in the version 3.1 User Guide. Thanks to Tom Slezak for revsing the get_genbank_file3 script and to Tod Stuber (USDA) for testing version 3.1 even though he doesn't need the annotation feature. All users are encouraged to upgrade to version 3.1.

Address of the bookmark: https://sourceforge.net/projects/ksnp/files/

assemblytics: delta file to analyze alignments of an assembly to another assembly or a reference genome

Jit — Thu, 14 Jun 2018 07:31:00 -0500

Download and install MUMmer Align your assembly to a reference genome using nucmer (from MUMmer package) $ nucmer -maxmatch -l 100 -c 500 REFERENCE.fa ASSEMBLY.fa -prefix OUT Consult the MUMmer manual if you encounter problems Optional: Gzip the delta file to speed up upload (usually 2-4X faster) $ gzip OUT.delta Then use the OUT.delta.gz file for upload. Upload the .delta or delta.gz file (view example) to Assemblytics Important: Use only contigs rather than scaffolds from the assembly. This will prevent false positives when the number of Ns in the scaffolded sequence does not match perfectly to the distance in the reference. The unique sequence length required represents an anchor for determining if a sequence is unique enough to safely call variants from, which is an alternative to the mapping quality filter for read alignment. http://assemblytics.com/

Address of the bookmark: http://assemblytics.com/

GAM-NGS: genomic assemblies merger for next generation sequencing

Jit — Fri, 19 May 2017 07:44:14 -0500

GAM-NGS is a tool able to merge two or more assemblies in order to improve contiguity and correctness. It can be used on all NGS-based assembly projects and it shows its full potential with multi-library Illumina-based projects. With more than 20 available assemblers it is hard to select the best tool. In this context we propose a tool that improves assemblies (and, as a by-product, perhaps even assemblers) by merging them and selecting the generating that is most likely to be correct.

Address of the bookmark: https://github.com/vice87/gam-ngs

CAMSA :: a tool for Comparative Analysis and Merging of Scaffold Assemblies

Rahul Nayak — Thu, 28 Dec 2017 09:10:26 -0600

CAMSA – is a tool for Comparative Analysis and Merging of Scaffold Assemblies, distributed both as a standalone software package and as Python library under the MIT license.

Main features:

works with any number of scaffold assemblies in de-novo non-progressive fashion
allows to simultaneously work with scaffold assemblies obtained from any in silico and in vitro techniques, supporting multiple existing formats via built-in converters
creates an extensive report with several comparative quality metrics (both on assembly level and on the level of individual assembly points)
constructs a merged combined scaffold assembly
provides an interactive framework for a visual comparative analysis of the given assemblies

Address of the bookmark: https://cblab.org/camsa/

SALSA: A tool to scaffold long read assemblies with Hi-C

Jit — Fri, 15 Jun 2018 04:01:15 -0500

This code is used to scaffold your assemblies using Hi-C data. This version implements some improvements in the original SALSA algorithm. If you want to use the old version, it can be found in the old_salsa branch. To use the latest version, first run the following commands: cd SALSA make To run the code, you will need Python 2.7, BOOST libraries and Networkx(version lower than 1.2). If you consider using this tool, please cite our publication which describes the methods used for scaffolding. Ghurye, J., Pop, M., Koren, S., Bickhart, D., & Chin, C. S. (2017). Scaffolding of long read assemblies using long range contact information. BMC genomics, 18(1), 527. Link Ghurye, J., Rhie, A., Walenz, B.P., Schmitt, A., Selvaraj, S., Pop, M., Phillippy, A.M. and Koren, S., 2018. Integrating Hi-C links with assembly graphs for chromosome-scale assembly. bioRxiv, p.261149 Link For any queries, please either ask on github issue page or send an email to Jay Ghurye (jayg@cs.umd.edu).

Address of the bookmark: https://github.com/machinegun/SALSA