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A physical map of the chicken genome.

Strategies for assembling large, complex genomes have evolved to include a combination of whole-genome shotgun sequencing and hierarchal map-assisted sequencing. Whole-genome maps of all types can aid genome assemblies, generally starting with low-resolution cytogenetic maps and ending with the highest resolution of sequence. Fingerprint clone maps are based upon complete restriction enzyme digests of clones representative of the target genome, and ultimately comprise a near-contiguous path of clones across the genome. Such clone-based maps are used to validate sequence assembly order, supply long-range linking information for assembled sequences, anchor sequences to the genetic map and provide templates for closing gaps. Fingerprint maps are also a critical resource for subsequent functional genomic studies, because they provide a redundant and ordered sampling of the genome with clones. In an accompanying paper we describe the draft genome sequence of the chicken, Gallus gallus, the first species sequenced that is both a model organism and a global food source. Here we present a clone-based physical map of the chicken genome at 20-fold coverage, containing 260 contigs of overlapping clones. This map represents approximately 91% of the chicken genome and enables identification of chicken clones aligned to positions in other sequenced genomes.

Animals↗

SilkDB: a knowledgebase for silkworm biology and genomics.

The Silkworm Knowledgebase (SilkDB) is a web-based repository for the curation, integration and study of silkworm genetic and genomic data. With the recent accomplishment of a approximately 6X draft genome sequence of the domestic silkworm (Bombyx mori), SilkDB provides an integrated representation of the large-scale, genome-wide sequence assembly, cDNAs, clusters of expressed sequence tags (ESTs), transposable elements (TEs), mutants, single nucleotide polymorphisms (SNPs) and functional annotations of genes with assignments to InterPro domains and Gene Ontology (GO) terms. SilkDB also hosts a set of ESTs from Bombyx mandarina, a wild progenitor of B.mori, and a collection of genes from other Lepidoptera. Comparative analysis results between the domestic and wild silkworm, between B.mori and other Lepidoptera, and between B.mori and the two sequenced insects, fruitfly and mosquito, are displayed by using B.mori genome sequence as a reference framework. Designed as a basic platform, SilkDB strives to provide a comprehensive knowledgebase about the silkworm and present the silkworm genome and related information in systematic and graphical ways for the convenience of in-depth comparative studies. SilkDB is publicly accessible at http://silkworm.genomics.org.cn.

Animals↗

RibAlign: a software tool and database for eubacterial phylogeny based on concatenated ribosomal protein subunits.

BACKGROUND: Until today, analysis of 16S ribosomal RNA (rRNA) sequences has been the de-facto gold standard for the assessment of phylogenetic relationships among prokaryotes. However, the branching order of the individual phlya is not well-resolved in 16S rRNA-based trees. In search of an improvement, new phylogenetic methods have been developed alongside with the growing availability of complete genome sequences. Unfortunately, only a few genes in prokaryotic genomes qualify as universal phylogenetic markers and almost all of them have a lower information content than the 16S rRNA gene. Therefore, emphasis has been placed on methods that are based on multiple genes or even entire genomes. The concatenation of ribosomal protein sequences is one method which has been ascribed an improved resolution. Since there is neither a comprehensive database for ribosomal protein sequences nor a tool that assists in sequence retrieval and generation of respective input files for phylogenetic reconstruction programs, RibAlign has been developed to fill this gap. RESULTS: RibAlign serves two purposes: First, it provides a fast and scalable database that has been specifically adapted to eubacterial ribosomal protein sequences and second, it provides sophisticated import and export capabilities. This includes semi-automatic extraction of ribosomal protein sequences from whole-genome GenBank and FASTA files as well as exporting aligned, concatenated and filtered sequence files that can directly be used in conjunction with the PHYLIP and MrBayes phylogenetic reconstruction programs. CONCLUSION: Up to now, phylogeny based on concatenated ribosomal protein sequences is hampered by the limited set of sequenced genomes and high computational requirements. However, hundreds of full and draft genome sequencing projects are on the way, and advances in cluster-computing and algorithms make phylogenetic reconstructions feasible even with large alignments of concatenated marker genes. RibAlign is a first step in this direction and may be particularly interesting to scientists involved in whole genome sequencing of representatives of new or sparsely studied eubacterial phyla. RibAlign is available at http://www.megx.net/ribalign.

Algorithms↗

The genome sequence of Mannheimia haemolytica A1: insights into virulence, natural competence, and Pasteurellaceae phylogeny.

The draft genome sequence of Mannheimia haemolytica A1, the causative agent of bovine respiratory disease complex (BRDC), is presented. Strain ATCC BAA-410, isolated from the lung of a calf with BRDC, was the DNA source. The annotated genome includes 2,839 coding sequences, 1,966 of which were assigned a function and 436 of which are unique to M. haemolytica. Through genome annotation many features of interest were identified, including bacteriophages and genes related to virulence, natural competence, and transcriptional regulation. In addition to previously described virulence factors, M. haemolytica encodes adhesins, including the filamentous hemagglutinin FhaB and two trimeric autotransporter adhesins. Two dual-function immunoglobulin-protease/adhesins are also present, as is a third immunoglobulin protease. Genes related to iron acquisition and drug resistance were identified and are likely important for survival in the host and virulence. Analysis of the genome indicates that M. haemolytica is naturally competent, as genes for natural competence and DNA uptake signal sequences (USS) are present. Comparison of competence loci and USS in other species in the family Pasteurellaceae indicates that M. haemolytica, Actinobacillus pleuropneumoniae, and Haemophilus ducreyi form a lineage distinct from other Pasteurellaceae. This observation was supported by a phylogenetic analysis using sequences of predicted housekeeping genes.

Actinobacillus pleuropneumoniae↗

A genome-wide survey of genes for enzymes involved in pigment synthesis in an ascidian, Ciona intestinalis.

The draft genome sequence and a large quantity of EST and cDNA information are now available for the ascidian Ciona intestinalis. In the present study, genes involved in pigment synthesis pathways were identified in the decoded genome of Ciona, and information about these genes was obtained from available EST and cDNA sequences. It was found that the Ciona genome contains orthologous genes for each enzyme of the melanin, pteridine, ommochrome, papiliochrome, and heme synthesis pathways. Several appear as independent duplications in the Ciona genome. Because cDNA clones for all but two of these genes have already been isolated by the cDNA project, C. intestinalis will provide an experimental system to explore molecular mechanisms underlying color patterns, through future genome-wide studies.

Animals↗

Genome sequence, comparative analysis and haplotype structure of the domestic dog.

Here we report a high-quality draft genome sequence of the domestic dog (Canis familiaris), together with a dense map of single nucleotide polymorphisms (SNPs) across breeds. The dog is of particular interest because it provides important evolutionary information and because existing breeds show great phenotypic diversity for morphological, physiological and behavioural traits. We use sequence comparison with the primate and rodent lineages to shed light on the structure and evolution of genomes and genes. Notably, the majority of the most highly conserved non-coding sequences in mammalian genomes are clustered near a small subset of genes with important roles in development. Analysis of SNPs reveals long-range haplotypes across the entire dog genome, and defines the nature of genetic diversity within and across breeds. The current SNP map now makes it possible for genome-wide association studies to identify genes responsible for diseases and traits, with important consequences for human and companion animal health.

Animals↗

Fugu ESTs: new resources for transcription analysis and genome annotation.

The draft Fugu rubripes genome was released in 2002, at which time relatively few cDNAs were available to aid in the annotation of genes. The data presented here describe the sequencing and analysis of 24,398 expressed sequence tags (ESTs) generated from 15 different adult and juvenile Fugu tissues, 74% of which matched protein database entries. Analysis of the EST data compared with the Fugu genome data predicts that approximately 10,116 gene tags have been generated, covering almost one-third of Fugu predicted genes. This represents a remarkable economy of effort. Comparison with the Washington University zebrafish EST assemblies indicates strong conservation within fish species, but significant differences remain. This potentially represents divergence of sequence in the 5' terminal exons and UTRs between these two fish species, although clearly, complete EST data sets are not available for either species. This project provides new Fugu resources, and the analysis adds significant weight to the argument that EST programs remain an essential resource for genome exploitation and annotation. This is particularly timely with the increasing availability of draft genome sequence from different organisms and the mounting emphasis on gene function and regulation.

Animals↗

Optimization of protoplast based DNA isolation and genome analysis in a gamma-irradiated Aspergillus niger mutant strain.

Aspergillus niger is an important industrial fungus widely used for citric acid production and a range of biotechnological applications. In this study, a protoplast-based DNA isolation protocol was optimized for a gamma-irradiated A. niger AN-L103_M1 mutant strain, followed by whole-genome sequencing and functional genome analysis. Protoplast yield was strongly influenced by enzyme concentration and the molarity of the osmotic stabilizer. The highest yield was achieved at an enzyme concentration of 50&#xa0;mg/mL (2.487&#x2009;&#xb1;&#x2009;0.04&#x2009;&#xd7;&#x2009;10&#x2078; cells/mL) and 0.8&#xa0;M KCl (2.550&#x2009;&#xb1;&#x2009;0.06&#x2009;&#xd7;&#x2009;10&#x2078; cells/mL), with both factors showing significant effects (p&#x2009;<&#x2009;0.0001) in GraphPad Prism 11.0.0. Whole-genome sequencing performed using an Illumina NovaSeq 6000 platform yielded a 37.06&#xa0;Mb draft genome assembled into 537 contigs, with an N50 of 363,084&#xa0;bp and a GC content of 48.2%. BUSCO 14 analysis showed high completeness (97.95% complete BUSCOs). Functional annotation and KEGG pathway mapping identified genes involved in glycolysis, the tricarboxylic acid cycle, and citrate biosynthesis, while biosynthetic gene cluster analysis revealed diverse potential for secondary metabolite production. These findings provide an optimized workflow for protoplast-based DNA isolation and genome-scale functional analysis in A. niger, proposing a basis for future comparative genomics, transformation studies, and experimentally validated metabolic engineering.

Aspergillus niger↗

The Neurospora crassa genome opens up the world of filamentous fungi.

The filamentous fungus Neurospora crassa, which has played an important role in the development of modern genetics, has several unique genome-defense mechanisms, including a process called repeat-induced point mutation. The draft genome sequence has revealed several unusual features, which suggest that the evolution of N. crassa has been greatly influenced by these defense mechanisms.

Animals↗

A genetic linkage map for the tiger pufferfish, Takifugu rubripes.

The compact genome of the tiger pufferfish, Takifugu rubripes (fugu), has been sequenced to the "draft" level and annotated to identify all the genes. However, the assembly of the draft genome sequence is highly fragmented due to the lack of a genetic or a physical map. To determine the long-range linkage relationship of the sequences, we have constructed the first genetic linkage map for fugu. The maps for the male and female spanning 697.1 and 1213.5 cM, respectively, were arranged into 22 linkage groups by markers heterozygous in both parents. The resulting map consists of 200 microsatellite loci physically linked to genome sequences spanning approximately 39 Mb in total. Comparisons of the genome maps of fugu, other teleosts, and mammals suggest that syntenic relationship is more conserved in the teleost lineage than in the mammalian lineage. Map comparisons also show a pufferfish lineage-specific rearrangement of the genome resulting in colocalization of two Hox gene clusters in one linkage group. This map provides a foundation for development of a complete physical map, a basis for comparison of long-range linkage of genes with other vertebrates, and a resource for mapping loci responsible for phenotypic differences among Takifugu species.

Animals↗

Draft sequencing and comparative genomics of Xylella fastidiosa strains reveal novel biological insights.

Draft sequencing is a rapid and efficient method for determining the near-complete sequence of microbial genomes. Here we report a comparative analysis of one complete and two draft genome sequences of the phytopathogenic bacterium, Xylella fastidiosa, which causes serious disease in plants, including citrus, almond, and oleander. We present highlights of an in silico analysis based on a comparison of reconstructions of core biological subsystems. Cellular pathway reconstructions have been used to identify a small number of genes, which are likely to reside within the draft genomes but are not captured in the draft assembly. These represented only a small fraction of all genes and were predominantly large and small ribosomal subunit protein components. By using this approach, some of the inherent limitations of draft sequence can be significantly reduced. Despite the incomplete nature of the draft genomes, it is possible to identify several phage-related genes, which appear to be absent from the draft genomes and not the result of insufficient sequence sampling. This region may therefore identify potential host-specific functions. Based on this first functional reconstruction of a phytopathogenic microbe, we spotlight an unusual respiration machinery as a potential target for biological control. We also predicted and developed a new defined growth medium for Xylella.

Attachment Sites, Microbiological↗

Whole-genome safety assessment of Loigolactobacillus coryniformis WBB05 and identification of a candidate gene for aerobic reuterin production.

This study reports on the safety profile of Loigolactobacillus coryniformis WBB05 for food industry applications and identifies glycerol-3-phosphate oxidase (GlpO) as a candidate gene associated with aerobic reuterin production. The safety of L. coryniformis WBB05 was evaluated through whole-genome sequencing, phenotypic analysis of haemolytic activity and determination of minimum inhibitory concentrations (MICs) of antibiotics. Comparative genomic analysis was performed to identify candidate genetic determinants for aerobic reuterin production. The draft genome (2.83 Mb, 179 contigs) harboured no known virulence factors, acquired antimicrobial resistance (AMR) genes or biogenic amine biosynthetic genes. Prophage analysis identified only one incomplete prophage region, and four CRISPR-Cas systems (212 spacers) were consistent with phage defence capacity. Secondary metabolite analysis revealed biosynthetic gene clusters encoding a coagulin-like bacteriocin. No &#x3b2;-haemolytic activity was observed. The MICs of all antibiotics tested were below the European Food Safety Authority cut-off values except for kanamycin (128&#xa0;mg/L), although no acquired AMR genes were detected. Comparative genomic analysis revealed that L. coryniformis WBB05 possesses two putative copies of GlpO, a gene not detected in publicly available genomes of Limosilactobacillus reuteri, which produces reuterin only under anaerobic conditions. These findings support the use of L. coryniformis WBB05 as a safe adjunct culture for dairy applications and highlight GlpO as a candidate determinant of aerobic reuterin production. Further studies comparing GlpO-positive and GlpO-negative strains under aerobic and anaerobic conditions are warranted to confirm the role of GlpO.

Loigolactobacillus coryniformis↗

Genome-wide investigation of intron length polymorphisms and their potential as molecular markers in rice (Oryza sativa L.).

Intron length polymorphisms (ILPs) have been used as genetic markers in some studies. However, a systematic investigation and large-scale exploitation of ILP markers has not been reported. In this study, we performed a genome-wide search of ILPs between two subspecies (indica and japonica) in rice using the draft genomic sequences of cultivars 93-11 (indica) and Nipponbare (japonica) and 32,127 full-length cDNA sequences of Nipponbare obtained from public databases. We identified 13,308 putative ILPs. Based on these putative ILPs, we developed 5811 candidate ILP markers via electronic-PCR with primers designed in flanking exons. We further conducted experiment to verify the candidate ILP markers. Out of 215 candidate ILP markers tested on 93-11, Nipponbare and their hybrid, we successfully exploited 173 codominant ILP markers. Further analyses on 10 rice accessions showed that these ILP markers were widely applicable and most (71.1%) exhibited subspecies specificity. This feature suggests that ILPs would be useful for the studies of genome evolution and inter-subspecies heterosis and for cross-subspecies marker-assisted selection in rice. In addition, by testing 51 pairs of the ILP primers on five Gramineae plants and three dicot plants, we found another desirable characteristic of rice ILP markers that they have high transferability to other plants.

Base Sequence↗

Genomes of the ex-type strains of Elsino&#xeb; mangiferae and E. perseae, the causal agents of scab on mango and avocado.

Elsino&#xeb; species are slow-growing, hemibiotrophic to necrotrophic fungi that cause scab diseases on economically important fruit crops. Genome resources for many host-specific species remain limited. We report high-quality draft genome assemblies for the ex-type strains of Elsino&#xeb; mangiferae (CBS 226.50) and E. perseae (CBS 406.34), causal agents of mango and avocado scab, respectively. Among 5 approaches tested, a Nanopore-only NextDenovo assembly produced the most contiguous genomes, yielding 24.5 Mb (E. mangiferae) and 25.1 Mb (E. perseae) assemblies with 13 and 18 contigs, respectively, BUSCO completeness scores of &#x223c;94%, and multiple putative telomere-to-telomere chromosomes. Gene prediction identified 9,134 and 9,243 genes, respectively. Functional annotation revealed enrichment of metabolic and regulatory pathways, including those involved in posttranslational modification, protein transport, and secondary metabolism. Carbohydrate-active enzyme repertoires were small but conserved, consistent with stealth pathogenicity strategies and low plant cell wall degradation. Both genomes encoded large secretomes (>850 proteins), diverse protease repertoires (>300 proteins), Ecp2-like effector proteins, and multiple biosynthetic gene clusters, including clusters with similarity to those associated with elsinochrome and ACT-toxin II biosynthesis, some of which may contribute to host-pathogen interactions and disease development. A large fraction of genes lacked functional characterization, suggesting incomplete databases and/or the presence of lineage-specific genes potentially involved in virulence or host adaptation. These genome resources fill critical gaps for underrepresented Elsino&#xeb; species and provide taxonomically anchored references essential for diagnostics, comparative genomics, and research into the molecular basis of host specificity and pathogenicity in scab-causing fungi.

Persea↗

Genome sequencing and annotation of two rhizobacteria with antifungal activity: Pseudomonas tolaasii strain A46 and Pseudomonas palleroriana P61.

Here, we report the draft genome sequences of P. tolaasii A46 and P. palleroriana P61, two rhizobacteria previously shown to inhibit Rhizoctonia solani. These genomic resources will support future efforts to elucidate the molecular basis of fungal suppression and to assess the biocontrol potential of these Pseudomonas strains.

antagonistic rhizobacteria↗

Utilization of a zebra finch BAC library to determine the structure of an avian androgen receptor genomic region.

The zebra finch (Taeniopygia guttata) is an important model organism for studying behavior, neuroscience, avian biology, and evolution. To support the study of its genome, we constructed a BAC library (TG__Ba) using DNA from livers of females. The BAC library consists of 147,456 clones with 98% containing inserts of an average size of 134 kb and represents 15.5 haploid genome equivalents. By sequencing a whole BAC, a full-length androgen receptor open reading frame was identified, the first in an avian species. Comparison of BAC end sequences and the whole BAC sequence with the chicken genome draft sequence showed a high degree of conserved synteny between the zebra finch and the chicken genome.

Animals↗

A high-resolution recombination map of the human genome.

Determination of recombination rates across the human genome has been constrained by the limited resolution and accuracy of existing genetic maps and the draft genome sequence. We have genotyped 5,136 microsatellite markers for 146 families, with a total of 1,257 meiotic events, to build a high-resolution genetic map meant to: (i) improve the genetic order of polymorphic markers; (ii) improve the precision of estimates of genetic distances; (iii) correct portions of the sequence assembly and SNP map of the human genome; and (iv) build a map of recombination rates. Recombination rates are significantly correlated with both cytogenetic structures (staining intensity of G bands) and sequence (GC content, CpG motifs and poly(A)/poly(T) stretches). Maternal and paternal chromosomes show many differences in locations of recombination maxima. We detected systematic differences in recombination rates between mothers and between gametes from the same mother, suggesting that there is some underlying component determined by both genetic and environmental factors that affects maternal recombination rates.

Base Sequence↗

Identification and expression pattern of Bmlark, a homolog of the Drosophila gene lark in Bombyx mori.

Two Bombyx mori isoforms of the gene lark, which is shown to play an important role in Drosophila circadian rhythms, were identified and named Bmlark-PA and Bmlark-PB, respectively. Bmlark-PA consists of 5 exons and encodes a protein of 343 amino acid residues which contains 3 functional domains: two RRM (RNA recognization motif) domains and an RTZF (retroviral-type zinc finger) and shares 72% identity with the Drosophila gene lark at the amino acid level. Bmlark-PB lacks the sequence between 118 and 791 nt of Bmlark-PA and codes for a protein of 68 amino acid residues, which contains no distinct functional domains. Alignments of the cDNAs of Bmlark to the genomic draft sequence of B. mori showed that the gene Bmlark had a single copy in the genome, suggesting that an alternative splicing mechanism occurs in the gene Bmlark. RT-PCR analysis indicated that Bmlark-PA was expressed only in late pupae and adult but Bmlark-PB was broadly expressed in many tissues and throughout the developmental stages from embryo to adult.

Alternative Splicing↗