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1.  PhylDiag: identifying complex synteny blocks that include tandem duplications using phylogenetic gene trees 
BMC Bioinformatics  2014;15(1):268.
Extant genomes share regions where genes have the same order and orientation, which are thought to arise from the conservation of an ancestral order of genes during evolution. Such regions of so-called conserved synteny, or synteny blocks, must be precisely identified and quantified, as a prerequisite to better understand the evolutionary history of genomes.
Here we describe PhylDiag, a software that identifies statistically significant synteny blocks in pairwise comparisons of eukaryote genomes. Compared to previous methods, PhylDiag uses gene trees to define gene homologies, thus allowing gene deletions to be considered as events that may break the synteny. PhylDiag also accounts for gene orientations, blocks of tandem duplicates and lineage specific de novo gene births. Starting from two genomes and the corresponding gene trees, PhylDiag returns synteny blocks with gaps less than or equal to the maximum gap parameter gapmax. This parameter is theoretically estimated, and together with a utility to graphically display results, contributes to making PhylDiag a user friendly method. In addition, putative synteny blocks are subject to a statistical validation to verify that they are unlikely to be due to a random combination of genes.
We benchmark several known metrics to measure 2D-distances in a matrix of homologies and we compare PhylDiag to i-ADHoRe 3.0 on real and simulated data. We show that PhylDiag correctly identifies small synteny blocks even with insertions, deletions, incorrect annotations or micro-inversions. Finally, PhylDiag allowed us to identify the most relevant distance metric for 2D-distance calculation between homologies.
Electronic supplementary material
The online version of this article (doi:10.1186/1471-2105-15-268) contains supplementary material, which is available to authorized users.
PMCID: PMC4155083  PMID: 25103980
Comparative genomics; Synteny; Synteny block; Segmental homologies; Homology; Gene order; Rearrangement; Ancestral genome; Gene tree
2.  The zebrafish reference genome sequence and its relationship to the human genome 
Howe, Kerstin | Clark, Matthew D. | Torroja, Carlos F. | Torrance, James | Berthelot, Camille | Muffato, Matthieu | Collins, John E. | Humphray, Sean | McLaren, Karen | Matthews, Lucy | McLaren, Stuart | Sealy, Ian | Caccamo, Mario | Churcher, Carol | Scott, Carol | Barrett, Jeffrey C. | Koch, Romke | Rauch, Gerd-Jörg | White, Simon | Chow, William | Kilian, Britt | Quintais, Leonor T. | Guerra-Assunção, José A. | Zhou, Yi | Gu, Yong | Yen, Jennifer | Vogel, Jan-Hinnerk | Eyre, Tina | Redmond, Seth | Banerjee, Ruby | Chi, Jianxiang | Fu, Beiyuan | Langley, Elizabeth | Maguire, Sean F. | Laird, Gavin K. | Lloyd, David | Kenyon, Emma | Donaldson, Sarah | Sehra, Harminder | Almeida-King, Jeff | Loveland, Jane | Trevanion, Stephen | Jones, Matt | Quail, Mike | Willey, Dave | Hunt, Adrienne | Burton, John | Sims, Sarah | McLay, Kirsten | Plumb, Bob | Davis, Joy | Clee, Chris | Oliver, Karen | Clark, Richard | Riddle, Clare | Eliott, David | Threadgold, Glen | Harden, Glenn | Ware, Darren | Mortimer, Beverly | Kerry, Giselle | Heath, Paul | Phillimore, Benjamin | Tracey, Alan | Corby, Nicole | Dunn, Matthew | Johnson, Christopher | Wood, Jonathan | Clark, Susan | Pelan, Sarah | Griffiths, Guy | Smith, Michelle | Glithero, Rebecca | Howden, Philip | Barker, Nicholas | Stevens, Christopher | Harley, Joanna | Holt, Karen | Panagiotidis, Georgios | Lovell, Jamieson | Beasley, Helen | Henderson, Carl | Gordon, Daria | Auger, Katherine | Wright, Deborah | Collins, Joanna | Raisen, Claire | Dyer, Lauren | Leung, Kenric | Robertson, Lauren | Ambridge, Kirsty | Leongamornlert, Daniel | McGuire, Sarah | Gilderthorp, Ruth | Griffiths, Coline | Manthravadi, Deepa | Nichol, Sarah | Barker, Gary | Whitehead, Siobhan | Kay, Michael | Brown, Jacqueline | Murnane, Clare | Gray, Emma | Humphries, Matthew | Sycamore, Neil | Barker, Darren | Saunders, David | Wallis, Justene | Babbage, Anne | Hammond, Sian | Mashreghi-Mohammadi, Maryam | Barr, Lucy | Martin, Sancha | Wray, Paul | Ellington, Andrew | Matthews, Nicholas | Ellwood, Matthew | Woodmansey, Rebecca | Clark, Graham | Cooper, James | Tromans, Anthony | Grafham, Darren | Skuce, Carl | Pandian, Richard | Andrews, Robert | Harrison, Elliot | Kimberley, Andrew | Garnett, Jane | Fosker, Nigel | Hall, Rebekah | Garner, Patrick | Kelly, Daniel | Bird, Christine | Palmer, Sophie | Gehring, Ines | Berger, Andrea | Dooley, Christopher M. | Ersan-Ürün, Zübeyde | Eser, Cigdem | Geiger, Horst | Geisler, Maria | Karotki, Lena | Kirn, Anette | Konantz, Judith | Konantz, Martina | Oberländer, Martina | Rudolph-Geiger, Silke | Teucke, Mathias | Osoegawa, Kazutoyo | Zhu, Baoli | Rapp, Amanda | Widaa, Sara | Langford, Cordelia | Yang, Fengtang | Carter, Nigel P. | Harrow, Jennifer | Ning, Zemin | Herrero, Javier | Searle, Steve M. J. | Enright, Anton | Geisler, Robert | Plasterk, Ronald H. A. | Lee, Charles | Westerfield, Monte | de Jong, Pieter J. | Zon, Leonard I. | Postlethwait, John H. | Nüsslein-Volhard, Christiane | Hubbard, Tim J. P. | Crollius, Hugues Roest | Rogers, Jane | Stemple, Derek L.
Nature  2013;496(7446):498-503.
Zebrafish have become a popular organism for the study of vertebrate gene function1,2. The virtually transparent embryos of this species, and the ability to accelerate genetic studies by gene knockdown or overexpression, have led to the widespread use of zebrafish in the detailed investigation of vertebrate gene function and increasingly, the study of human genetic disease3–5. However, for effective modelling of human genetic disease it is important to understand the extent to which zebrafish genes and gene structures are related to orthologous human genes. To examine this, we generated a high-quality sequence assembly of the zebrafish genome, made up of an overlapping set of completely sequenced large-insert clones that were ordered and oriented using a high-resolution high-density meiotic map. Detailed automatic and manual annotation provides evidence of more than 26,000 protein-coding genes6, the largest gene set of any vertebrate so far sequenced. Comparison to the human reference genome shows that approximately 70% of human genes have at least one obvious zebrafish orthologue. In addition, the high quality of this genome assembly provides a clearer understanding of key genomic features such as a unique repeat content, a scarcity of pseudogenes, an enrichment of zebrafish-specific genes on chromosome 4 and chromosomal regions that influence sex determination.
PMCID: PMC3703927  PMID: 23594743
3.  Ensembl 2014 
Nucleic Acids Research  2013;42(Database issue):D749-D755.
Ensembl ( creates tools and data resources to facilitate genomic analysis in chordate species with an emphasis on human, major vertebrate model organisms and farm animals. Over the past year we have increased the number of species that we support to 77 and expanded our genome browser with a new scrollable overview and improved variation and phenotype views. We also report updates to our core datasets and improvements to our gene homology relationships from the addition of new species. Our REST service has been extended with additional support for comparative genomics and ontology information. Finally, we provide updated information about our methods for data access and resources for user training.
PMCID: PMC3964975  PMID: 24316576
4.  TreeFam v9: a new website, more species and orthology-on-the-fly 
Nucleic Acids Research  2013;42(Database issue):D922-D925.
TreeFam ( is a database of phylogenetic trees inferred from animal genomes. For every TreeFam family we provide homology predictions together with the evolutionary history of the genes. Here we describe an update of the TreeFam database. The TreeFam project was resurrected in 2012 and has seen two releases since. The latest release (TreeFam 9) was made available in March 2013. It has orthology predictions and gene trees for 109 species in 15 736 families covering ∼2.2 million sequences. With release 9 we made modifications to our production pipeline and redesigned our website with improved gene tree visualizations and Wikipedia integration. Furthermore, we now provide an HMM-based sequence search that places a user-provided protein sequence into a TreeFam gene tree and provides quick orthology prediction. The tool uses Mafft and RAxML for the fast insertion into a reference alignment and tree, respectively. Besides the aforementioned technical improvements, we present a new approach to visualize gene trees and alternative displays that focuses on showing homology information from a species tree point of view. From release 9 onwards, TreeFam is now hosted at the EBI.
PMCID: PMC3965059  PMID: 24194607
5.  Sequencing of the sea lamprey (Petromyzon marinus) genome provides insights into vertebrate evolution 
Nature genetics  2013;45(4):415-421e2.
Lampreys are representatives of an ancient vertebrate lineage that diverged from our own ~500 million years ago. By virtue of this deeply shared ancestry, the sea lamprey (P. marinus) genome is uniquely poised to provide insight into the ancestry of vertebrate genomes and the underlying principles of vertebrate biology. Here, we present the first lamprey whole-genome sequence and assembly. We note challenges faced owing to its high content of repetitive elements and GC bases, as well as the absence of broad-scale sequence information from closely related species. Analyses of the assembly indicate that two whole-genome duplications likely occurred before the divergence of ancestral lamprey and gnathostome lineages. Moreover, the results help define key evolutionary events within vertebrate lineages, including the origin of myelin-associated proteins and the development of appendages. The lamprey genome provides an important resource for reconstructing vertebrate origins and the evolutionary events that have shaped the genomes of extant organisms.
PMCID: PMC3709584  PMID: 23435085
6.  Plasticity of Animal Genome Architecture Unmasked by Rapid Evolution of a Pelagic Tunicate 
Science (New York, N.Y.)  2010;330(6009):1381-1385.
Genomes of animals as different as sponges and humans show conservation of global architecture. Here we show that multiple genomic features including transposon diversity, developmental gene repertoire, physical gene order, and intron-exon organization are shattered in the tunicate Oikopleura, belonging to the sister group of vertebrates and retaining chordate morphology. Ancestral architecture of animal genomes can be deeply modified and may therefore be largely nonadaptive. This rapidly evolving animal lineage thus offers unique perspectives on the level of genome plasticity. It also illuminates issues as fundamental as the mechanisms of intron gain.
PMCID: PMC3760481  PMID: 21097902
7.  Ensembl 2013 
Nucleic Acids Research  2012;41(Database issue):D48-D55.
The Ensembl project ( provides genome information for sequenced chordate genomes with a particular focus on human, mouse, zebrafish and rat. Our resources include evidenced-based gene sets for all supported species; large-scale whole genome multiple species alignments across vertebrates and clade-specific alignments for eutherian mammals, primates, birds and fish; variation data resources for 17 species and regulation annotations based on ENCODE and other data sets. Ensembl data are accessible through the genome browser at and through other tools and programmatic interfaces.
PMCID: PMC3531136  PMID: 23203987
8.  Genomicus: five genome browsers for comparative genomics in eukaryota 
Nucleic Acids Research  2012;41(Database issue):D700-D705.
Genomicus ( is a database and an online tool that allows easy comparative genomic visualization in >150 eukaryote genomes. It provides a way to explore spatial information related to gene organization within and between genomes and temporal relationships related to gene and genome evolution. For the specific vertebrate phylum, it also provides access to ancestral gene order reconstructions and conserved non-coding elements information. We extended the Genomicus database originally dedicated to vertebrate to four new clades, including plants, non-vertebrate metazoa, protists and fungi. This visualization tool allows evolutionary phylogenomics analysis and exploration. Here, we describe the graphical modules of Genomicus and show how it is capable of revealing differential gene loss and gain, segmental or genome duplications and study the evolution of a locus through homology relationships.
PMCID: PMC3531091  PMID: 23193262
9.  Toward community standards in the quest for orthologs 
Bioinformatics  2012;28(6):900-904.
The identification of orthologs—genes pairs descended from a common ancestor through speciation, rather than duplication—has emerged as an essential component of many bioinformatics applications, ranging from the annotation of new genomes to experimental target prioritization. Yet, the development and application of orthology inference methods is hampered by the lack of consensus on source proteomes, file formats and benchmarks. The second ‘Quest for Orthologs’ meeting brought together stakeholders from various communities to address these challenges. We report on achievements and outcomes of this meeting, focusing on topics of particular relevance to the research community at large. The Quest for Orthologs consortium is an open community that welcomes contributions from all researchers interested in orthology research and applications.
PMCID: PMC3307119  PMID: 22332236
10.  Ensembl 2012 
Nucleic Acids Research  2011;40(Database issue):D84-D90.
The Ensembl project ( provides genome resources for chordate genomes with a particular focus on human genome data as well as data for key model organisms such as mouse, rat and zebrafish. Five additional species were added in the last year including gibbon (Nomascus leucogenys) and Tasmanian devil (Sarcophilus harrisii) bringing the total number of supported species to 61 as of Ensembl release 64 (September 2011). Of these, 55 species appear on the main Ensembl website and six species are provided on the Ensembl preview site (Pre!Ensembl; with preliminary support. The past year has also seen improvements across the project.
PMCID: PMC3245178  PMID: 22086963
11.  Genomicus: a database and a browser to study gene synteny in modern and ancestral genomes 
Bioinformatics  2010;26(8):1119-1121.
Summary: Comparative genomics remains a pivotal strategy to study the evolution of gene organization, and this primacy is reinforced by the growing number of full genome sequences available in public repositories. Despite this growth, bioinformatic tools available to visualize and compare genomes and to infer evolutionary events remain restricted to two or three genomes at a time, thus limiting the breadth and the nature of the question that can be investigated. Here we present Genomicus, a new synteny browser that can represent and compare unlimited numbers of genomes in a broad phylogenetic view. In addition, Genomicus includes reconstructed ancestral gene organization, thus greatly facilitating the interpretation of the data.
Availability: Genomicus is freely available for online use at while data can be downloaded at
PMCID: PMC2853686  PMID: 20185404

Results 1-11 (11)