BOL: Related items

Is reference genome necessary for gene expression study in transcriptome sequencing or for variant discovery in genome sequencing?

Rahul Agarwal — Wed, 17 Jul 2013 15:25:09 -0500

Like in case of plant genomes where nature of genome is too complex and huge in size to accomplish complete de novo assembly by current sequencing technology. What would be alternate solution? Can we live in reference free world?

Sorghum genome Sequenced!!

Jit — Sun, 01 Sep 2013 19:46:18 -0500

Sorghum, a staple food for 500 million resource-poor people in marginal environments and a model for other important crops, sorghum holds vital genetic resources as humanity confronts the nexus of food crisis and climate change. The recent research provides an unmatched resource to respond to these challenges by identifying a large high-quality SNP and indel data set in diverse sorghum genotypes.

In addition to providing a broad sample of the diversity in S. bicolor, the genotypes included in this study are known to display agronomically important traits including stay-green drought resistance, insect resistance, grain size and grain quality.

Find more at http://www.nature.com/ncomms/2013/130827/ncomms3320/full/ncomms3320.html

Genetics, epigenetics and disease

Fri, 27 Sep 2013 11:32:55 -0500

Royal Society GlaxoSmithKline Prize Lecture given by Professor Adrian Bird CBE FMedSci FRS on Tuesday 22 January 2013. Adrian Bird CBE FMedSci FRS is the Buchanan Chair of Genetics at the University of Edinburgh. The human genome sequence has been available for more than a decade, but its significance is still not fully understood. While most human genes have been identified, there is much to learn about the DNA signals that control them. This lecture described an unusually short DNA sequence, just two base pairs long, CG, which occurs in several chemically different forms. Defects in signalling by CG are implicated in disease. For example, the autism spectrum disorder Rett syndrome is caused by loss of a protein that reads methylated CG and affects the activity of genes. The Royal Society GlaxoSmithKline Prize Lecture is awarded for original contributions to medical and veterinary sciences published within ten years from the date of the award.

Alien Genome !!!

Jit — Sat, 13 Dec 2014 00:24:32 -0600

Genome sequencing, analysis and expression of Alien genome.

Note: This image/cartoon is create only for fun. It has nothing to do with any scientific findings.

Genome Annotation Transfer Utility (GATU)

Jit — Mon, 29 May 2017 05:54:53 -0500

Genome Annotation Transfer Utility (GATU) was designed to facilitate quick, efficient annotation of similar genomes using genomes that have already been annotated. For example, whenever a new strain of SARS coronavirus is sequenced, it is possible, using GATU, to automatically annotate the new strain using a previously-annotated strain of SARS CoV. This saves researchers from tedious manual annotation of these sequences.

The program utilizes tBLASTn and BLASTn algorithms to map genes from the reference genome (the annotated strain) to the new sequence (the unannotated strain). The goal is to annotate the majority of the new genome’s genes in a single step. ORFs present in the target genome and absent from the reference genome are also identified; these ORFs can be further analyzed using BLAST, VGO and BBB. Afterwards, they can either be accepted for/rejected from annotation. GATU can handle multiple-exon genes as well as mature peptides. Although it was designed for use with viral genomes, GATU can also be used to help annotate larger genomes (ie. bacterial genomes).

The output is saved in GenBank, XML, or EMBL file format.

Address of the bookmark: https://virology.uvic.ca/help/tool-help/help-books/genome-annotation-transfer-utility-gatu-documentation/

Oxford Nanopore Sequencing, Hybrid Error Correction, and de novo Assembly of a Eukaryotic Genome

Jit — Wed, 29 Nov 2017 05:08:53 -0600

Monitoring the progress of DNA molecules through a membrane pore has been postulated as a method for sequencing DNA for several decades. Recently, a nanopore-based sequencing instrument, the Oxford Nanopore MinION, has become available that we used for sequencing the S. cerevisiae genome. To make use of these data, we developed a novel open-source hybrid error correction algorithm Nanocorr (https://github.com/jgurtowski/nanocorr) specifically for Oxford Nanopore reads, as existing packages were incapable of assembling the long read lengths (5-50kbp) at such high error rate (between ~5 and 40% error). With this new method we were able to perform a hybrid error correction of the nanopore reads using complementary MiSeq data and produce a de novo assembly that is highly contiguous and accurate: the contig N50 length is more than ten-times greater than an Illumina-only assembly (678kb versus 59.9kbp), and has greater than 99.88% consensus identity when compared to the reference. Furthermore, the assembly with the long nanopore reads presents a much more complete representation of the features of the genome and correctly assembles gene cassettes, rRNAs, transposable elements, and other genomic features that were almost entirely absent in the Illumina-only assembly.

Address of the bookmark: http://schatzlab.cshl.edu/data/nanocorr/

Genome assembly stats plotting

Jit — Wed, 28 Feb 2018 03:45:39 -0600

A de novo genome assembly can be summarised b

y a number of metrics, including:

Overall assembly length
Number of scaffolds/contigs
Length of longest scaffold/contig
Scaffold/contig N50 and N90Assembly base composition, in particular percentage GC and percentage Ns
CEGMA completeness
Scaffold/contig length/count distribution

assembly-stats supports two widely used presentations of these values, tabular and cumulative length plots, and introduces an additional circular plot that summarises most commonly used assembly metrics in a single visualisation. Each of these presentations is generated using javascript from a common (JSON) data structure, allowing toggling between alternative views, and each can be applied to a single or multiple assemblies to allow direct comparison of alternate assemblies.

Tabular presentation allows direct comparison of exact values between assemblies, the limitations of this approach lie in the necessary omission of distributions and the challenge of interpreting ratios of values that may vary by several orders of magnitude.

Address of the bookmark: https://github.com/rjchallis/assembly-stats

The MARVEL assembler

Jit — Fri, 04 May 2018 19:18:41 -0500

MARVEL consists of a set of tools that facilitate the overlapping, patching, correction and assembly of noisy (not so noisy ones as well) long reads.

The assembly process can be summarized as follows:

overlap
patch reads
overlap (again)
scrubbing
assembly graph construction and touring
optional read correction
fasta file creation

Address of the bookmark: https://github.com/schloi/MARVEL

CGView - Circular Genome Viewer

Rahul Nayak — Wed, 20 Jun 2018 10:15:57 -0500

CGView is a Java package for generating high quality, zoomable maps of circular genomes. Its primary purpose is to serve as a component of sequence annotation pipelines, as a means of generating visual output suitable for the web. Feature information and rendering options are supplied to the program using an XML file, a tab delimited file, or an NCBI ptt file. CGView converts the input into a graphical map (PNG, JPG, or Scalable Vector Graphics format), complete with labels, a title, legends, and footnotes. In addition to the default full view map, the program can generate a series of hyperlinked maps showing expanded views. The linked maps can be explored using any web browser, allowing rapid genome browsing, and facilitating data sharing. The feature labels in maps can be hyperlinked to external resources, allowing CGView maps to be integrated with existing web site content or databases. For examples of the various output types, see the CGView gallery. http://wishart.biology.ualberta.ca/cgview/gallery.html http://stothard.afns.ualberta.ca/downloads/CCT/index.html https://www.gview.ca/wiki/GView/WebHome https://server.gview.ca/ http://stothard.afns.ualberta.ca/cgview_server/ Paper https://academic.oup.com/bib/advance-article/doi/10.1093/bib/bbx081/4037458

Address of the bookmark: http://wishart.biology.ualberta.ca/cgview/

You can't hide from Genome Hackers

Neel — Sat, 13 Oct 2018 14:17:28 -0500

Young computational biologist named Yaniv Erlich shocked the research world by showing it was possible to unmask the identities of people listed in anonymous genetic databases using only an Internet connection

Paper: http://science.sciencemag.org/content/early/2018/10/10/science.aau4832

More at https://www.wired.com/story/genome-hackers-show-no-ones-dna-is-anonymous-anymore/