Genome Annotation

Sequencing projects arising from high-throughput technologies including those of sequencing DNA microarray allowed measuring simultaneously the expression levels of millions of genes of a biological sample as well as to annotate and to identify the role (function) of those genes. Consequently, to better manage and organize this significant amount of information, bioinformatics approaches have been developed. These approaches provide a representation and a more 'relevant' integration of data in order to test and validate the researchers' hypothesis. In this context, this article describes and discusses some techniques used for the functional analysis of gene expression data.

The Bovine Genome Database (BGD; http://BovineGenome.org) strives to improve annotation of the bovine genome and to integrate the genome sequence with other genomics data. BGD includes GBrowse genome browsers, the Apollo Annotation Editor, a quantitative trait loci (QTL) viewer, BLAST databases and gene pages. Genome browsers, available for both scaffold and chromosome coordinate systems, display the bovine Official Gene Set (OGS), RefSeq and Ensembl gene models, non-coding RNA, repeats, pseudogenes, single-nucleotide polymorphism, markers, QTL and alignments to complementary DNAs, ESTs and protein homologs. The Bovine QTL viewer is connected to the BGD Chromosome GBrowse, allowing for the identification of candidate genes underlying QTL. The Apollo Annotation Editor connects directly to the BGD Chado database to provide researchers with remote access to gene evidence in a graphical interface that allows editing and creating new gene models. Researchers may upload their annotations to the BGD server for review and integration into the subsequent release of the OGS. Gene pages display information for individual OGS gene models, including gene structure, transcript variants, functional descriptions, gene symbols, Gene Ontology terms, annotator comments and links to National Center for Biotechnology Information and Ensembl. Each gene page is linked to a wiki page to allow input from the research community.

Objective: The Arabidopsis thaliana Niederzenz-1 genome sequence was recently published with an ab initio gene prediction. In depth analysis of the predicted gene set revealed some errors involving genes with non-canonical splice sites in their introns. Since non-canonical splice sites are difficult to predict ab initio, we checked for options to improve the annotation by transferring annotation information from the recently released Columbia-0 reference genome sequence annotation Araport11. Results: Incorporation of hints generated from Araport11 enabled the precise prediction of non-canonical splice sites. Manual inspection of RNA-Seq read mapping and RT-PCR were applied to validate the structural annotations of non-canonical splice sites. Predictions of untranslated regions were also updated by harnessing the potential of Araport11's information, which was generated by using high coverage RNA-Seq data. The improved gene set of the Nd-1 genome assembly (GeneSet_Nd-1_v1.1) was evaluated via comparison to the initial gene prediction (Gen-eSet_Nd-1_v1.0) as well as against Araport11 for the Col-0 reference genome sequence. GeneSet_Nd-1_v1.1 contains previously missed non-canonical splice sites in 1256 genes. Reciprocal best hits for 24,527 (89.4%) of all nuclear Col-0 genes against the GeneSet_Nd-1_v1.1 indicate a high gene prediction quality.

Genome annotation plays an essential role in the interpretation and use of genome sequence information. While great strides have been made in the annotation of coding regions of genes, less success has been achieved in the annotation of the regulatory regions of genes, including promoters, enhancers/silencers, and other regulatory elements. One reason for this disparity in annotated information is that coding regions can be assessed using high-throughput techniques such as EST sequencing, while annotation of regulatory regions often requires a gene-by-gene approach. The NFI-Regulome database http://nfiregulome.ccr.buffalo.edu was designed to promote easy annotation of the regulatory regions of genes that contain binding sites for the NFI (Nuclear Factor I) family of transcription factors, using data from the published literature. Binding sites are annotated together with the sequence of the gene, obtained from the UCSC Genome site, and the locations of all binding sites for multiple...

European hazelnut (Corylus avellana L.) is
of worldwide agricultural signifi cance, with
breeding efforts focused on combining high nut
yield and nut quality with resistance to diseases
such as eastern fi lbert blight (EFB), a cause of
severe crop loss in much of the United States.
Oregon State University recently released a
resistant cultivar, ‘Jefferson’ (OSU 703.007),
that was chosen for transcriptome sequencing
to establish further genomic resources for
C. avellana L. We used Illumina ribonucleic
acid sequencing (RNA-seq) to characterize
complementary DNA (cDNA) libraries from four
hazelnut tissues, including leaves, catkins, bark,
and whole seedlings. The 6.8 Gb of hazelnut
transcriptome data was assembled de novo
into 28,255 contigs with an average length of
532 bp and an N50 (the minimum contig length
necessary such that all contigs of equal or
greater length will equal half of the bases of the
assembly) of 961 bp. Sequence comparisons
using BLASTX and gene ontology (GO)
classifi cations were used to generate automated
descriptive function annotations. High similarity
of the predicted proteins to sequences in
related plants demonstrates the validity of the
transcript contigs, with 80.8% having similarity
to grape (Vitis vinifera L.), poplar (Populus
trichocarpa Torr. & A. Gray), and castor bean
(Ricinus communis L.) sequences in the public
domain. A survey of GO terms enriched among
tissue-specifi c transcripts further validates
the assembly. A basic local alignment search
tool (BLAST) portal and web resources (http://
hazelnut.cgrb.oregonstate.edu [accessed 8 Jan.
2010]) are available and will be of importance to
breeders for marker-assisted breeding efforts.

Fungal genome annotation is the starting point for analysis of genome content. This generally involves the application of diverse methods to identify features on a genome assembly such as protein-coding and non-coding genes, repeats and transposable elements, and pseudogenes. Here, we describe tools and methods leveraged for eukaryotic genome annotation with a focus on the annotation of fungal nuclear and

Classical laboratory inbred strains of mice have been extremely helpful for research in immunology and oncology, and more generally, for the analysis of complex traits. Unfortunately, because they all derive from a relatively small pool of ancestors, their genetic polymorphism is rather limited. However, recently strains belonging to different species of Mus have been established from wild progenitors. These are an interesting addition to the arsenal of mouse geneticists, because they can be crossed with classical laboratory strains to produce viable and fertile offspring with a large number of polymorphisms of natural origin. These strains are helpful for making genome annotations because they permit highly refined genotype–phenotype correlations. They also allow the interpretation of molecular variation within a clear evolutionary framework. In this article, we provide examples with the aim of promoting the use of these new strains.

Background Corynebacterium pseudotuberculosis is generally regarded as an important animal pathogen that rarely infects humans. Clinical strains are occasionally recovered from human cases of lymphadenitis, such as C. pseudotuberculosis FRC41 that was isolated from the inguinal lymph node of a 12-year-old girl with necrotizing lymphadenitis. To detect potential virulence factors and corresponding gene-regulatory networks in this human isolate, the genome sequence of C. pseudotuberculosis FCR41 was determined by pyrosequencing and functionally annotated. Results Sequencing and assembly of the C. pseudotuberculosis FRC41 genome yielded a circular chromosome with a size of 2,337,913 bp and a mean G+C content of 52.2%. Specific gene sets associated with iron and zinc homeostasis were detected among the 2,110 predicted protein-coding regions and integrated into a gene-regulatory network that is linked with both the central metabolism and the oxidative stress response of FRC41. Two gene c...