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Phylogenomics, the study of phylogenetic relationships among taxa based on their genome sequences, has emerged as the preferred phylogenetic method because of the wealth of phylogenetic information contained in genome sequences. Genome sequencing, however, can be prohibitively expensive, especially for taxa with huge genomes and when many taxa need sequencing. Consequently, the less costly phylotranscriptomics has seen an increased use in recent years. Phylotranscriptomics reconstructs phylogenies using DNA sequences derived from transcriptomes, which are often orders of magnitude smaller than genomes. However, in the absence of corresponding genome sequences, comparative analyses of transcriptomes can be challenging and it is unclear whether phylotranscriptomics is as reliable as phylogenomics. Here, we respectively compare the phylogenomic and phylotranscriptomic trees of 22 mammals and 15 plants that have both sequenced nuclear genomes and publicly available RNA sequencing data from multiple tissues. We found that phylotranscriptomic analysis can be sensitive to orthologous gene identification. When a rigorous method for identifying orthologs is employed, phylogenomic and phylotranscriptomic trees are virtually identical to each other, regardless of the tissue of origin of the transcriptomes and whether the same tissue is used across species. These findings validate phylotranscriptomics, brighten its prospect, and illustrate the criticality of reliable ortholog detection in such practices.

Made available in DSpace on 2019-10-06T16:35:19Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-01-01. Added 1 bitstream(s) on 2019-10-09T18:35:28Z : No. of bitstreams: 1 S1415-47572019000100145.pdf: 1807906 bytes, checksum: 429de26cfda2d5142dade2f2716528e9 (MD5) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) The filter cake from sugar cane processing is rich in organic matter and nutrients, which favors the proliferation of microorganisms with potential to deconstruct plant biomass. From the metagenomic data of this material, we assembled a draft genome that was phylogenetically related to Thermomonospora curvata DSM 43183, which shows the functional and ecological importance of this bacterium in the filter cake. Thermomonospora is a gram-positive bacterium that produces cellulases in compost, and it can survive temperatures of 60 ºC. We identified a complete set of biomass depolymerizing enzymes in the draft genome of Thermomonospora sp. CIT 1, such as α-amylase, catalase-peroxidases, β-mannanase, and arabinanase, demonstrating the potential of this bacterium to deconstruct the components of starch, lignin, and hemicellulose. In addition, the draft genome of Thermomonospora sp. CIT 1 contains 18 genes that do not share identity with five other species of Thermomonospora, suggesting that this bacterium has different genetic characteristics than those present in genomes reported so far for this genus. These findings add a new dimension to the current understanding of the functional profile of this microorganism that inhabits agro-industrial waste, which may boost new gene discoveries and be of importance for application in the production of bioethanol. Faculdade de Ciências Agrárias e Veterinárias Universidade Estadual Paulista (UNESP) Departamento de Tecnologia Laboratório de Bioinformática Faculdade de Ciências Agrárias e Veterinárias Universidade Estadual Paulista (UNESP) Laboratório Multiusuário Centralizado para Sequenciamento de DNA em Larga Escala e Análise de Expressão Gênica (LMSeq) Faculdade de Ciências Agrárias e Veterinárias Universidade Estadual Paulista (UNESP) Departamento de Biologia Aplicada à Agropecuária Laboratório de Genética Aplicada Faculdade de Ciências Agrárias e Veterinárias Universidade Estadual Paulista (UNESP) Faculdade de Ciências Agrárias e Veterinárias Universidade Estadual Paulista (UNESP) Departamento de Tecnologia Laboratório de Bioinformática Faculdade de Ciências Agrárias e Veterinárias Universidade Estadual Paulista (UNESP) Laboratório Multiusuário Centralizado para Sequenciamento de DNA em Larga Escala e Análise de Expressão Gênica (LMSeq) Faculdade de Ciências Agrárias e Veterinárias Universidade Estadual Paulista (UNESP) Departamento de Biologia Aplicada à Agropecuária Laboratório de Genética Aplicada Faculdade de Ciências Agrárias e Veterinárias Universidade Estadual Paulista (UNESP)

The micronutrients iron (Fe) and zinc (Zn) are not only essential for plant survival and proliferation but are crucial for human health. Increasing Fe and Zn levels in edible parts of plants, known as biofortification, is seen a sustainable approach to alleviate micronutrient deficiency in humans. Wheat, as one of the leading staple foods worldwide, is recognized as a prioritized choice for Fe and Zn biofortification. However, to date, limited molecular and physiological mechanisms have been elucidated for Fe and Zn homeostasis in wheat. The expanding molecular understanding of Fe and Zn homeostasis in model plants is providing invaluable resources to biofortify wheat. Recent advancements in NGS (next generation sequencing) technologies coupled with improved wheat genome assembly and high-throughput genotyping platforms have initiated a revolution in resources and approaches for wheat genetic investigations and breeding. Here, we summarize molecular processes and genes involved in Fe and Zn homeostasis in the model plants Arabidopsis and rice, identify their orthologs in the wheat genome, and relate them to known wheat Fe/Zn QTL (quantitative trait locus/loci) based on physical positions. The current study provides the first inventory of the genes regulating grain Fe and Zn homeostasis in wheat, which will benefit gene discovery and breeding, and thereby accelerate the release of Fe- and Zn-enriched wheats.

Significance This work represents a large, order-wide evolutionary analysis of the order Chiroptera (bats). Our pipeline for assembling sequence data and curating orthologous multiple sequence alignments includes methods for improving results when combining genomic and transcriptomic data sources. The resulting phylogenetic tree divides the order Chiroptera into Yinpterochiroptera and Yangochiroptera, in disagreement with the previous division into Megachiroptera and Microchiroptera and in agreement with some other recent molecular studies, and also provides evidence for other contested branch placements. We also performed a genome-wide analysis of positive selection and found 181 genes with signatures of positive selection. Enrichment analysis shows these positively selected genes to be primarily related to immune responses but also, surprisingly, collagen formation., Historically, the evolution of bats has been analyzed using a small number of genetic loci for many species or many genetic loci for a few species. Here we present a phylogeny of 18 bat species, each of which is represented in 1,107 orthologous gene alignments used to build the tree. We generated a transcriptome sequence of Hypsignathus monstrosus, the African hammer-headed bat, and additional transcriptome sequence for Rousettus aegyptiacus, the Egyptian fruit bat. We then combined these data with existing genomic and transcriptomic data from 16 other bat species. In the analysis of such datasets, there is no clear consensus on the most reliable computational methods for the curation of quality multiple sequence alignments since these public datasets represent multiple investigators and methods, including different source materials (chromosomal DNA or expressed RNA). Here we lay out a systematic analysis of parameters and produce an advanced pipeline for curating orthologous gene alignments from combined transcriptomic and genomic data, including a software package: the Mismatching Isoform eXon Remover (MIXR). Using this method, we created alignments of 11,677 bat genes, 1,107 of which contain orthologs from all 18 species. Using the orthologous gene alignments created, we assessed bat phylogeny and also performed a holistic analysis of positive selection acting in bat genomes. We found that 181 genes have been subject to positive natural selection. This list is dominated by genes involved in immune responses and genes involved in the production of collagens.

International audience; Plant cell walls play a fundamental role in several plant traits and also influence crop use as livestock nutrition or biofuel production. The Glycosyltransferase family 61 (GT61) is involved in the synthesis of cell wall xylans. In grasses (Poaceae), a copy number expansion was reported for the GT61 family, and raised the question of the evolutionary history of this gene family in a broader taxonomic context. A phylogenetic study was performed on GT61 members from 13 species representing the major angiosperm clades, in order to classify the genes, reconstruct the evolutionary history of this gene family and study its expansion in monocots. Four orthogroups (OG) were identified in angiosperms with two of them displaying a copy number expansion in monocots. These copy number expansions resulted from both tandem and segmental duplications during the genome evolution of monocot lineages. Positive selection footprints were detected on the ancestral branch leading to one of the orthogroups suggesting that the gene number expansion was accompanied by functional diversification, at least partially. We propose an OG-based classification framework for the GT61 genes at different taxonomic levels of the angiosperm useful for any further functional or translational biology study.

Background Polyploidy is considered a major driving force in genome expansion, yielding duplicated genes whose expression may be conserved or divergence as a consequence of polyploidization. Results We compared the genome sequences of tetraploid cotton (Gossypium hirsutum) and its two diploid progenitors, G. arboreum and G. raimondii, and found that the bHLH genes were conserved over the polyploidization. Oppositely, the expression of the homeolgous gene pairs was diversified. The biased homeologous proportion for bHLH family is significantly higher (64.6%) than the genome wide homeologous expression bias (40%). Compared with cacao (T. cacao), orthologous genes only accounted for a small proportion (41.7%) of whole cotton bHLHs family. The further Ks analysis indicated that bHLH genes underwent at least two distinct episodes of whole genome duplication: a recent duplication (1.0–60.0 million years ago, MYA, 0.005 60.0 MYA, 0.312

Many important crops have received little attention by the scientific community, either because they are not considered economically important or due to their large and complex genomes. De novo transcriptome assembly, using next-generation sequencing data, is an attractive option for the study of these orphan crops. In spite of the large amount of sequencing data that can be generated, there is currently a lack of tools which can effectively help molecular breeders and biologists to mine this type of information. Our goal was to develop a tool that enables molecular breeders, without extensive bioinformatics knowledge, to efficiently study de novo transcriptome data from any orphan crop (http://www.bioinformatics.nl/denovobrowser/db/species/index). The Orphan Crops Browser has been designed to facilitate the following tasks (1) search and identification of candidate transcripts based on phylogenetic relationships between orthologous sequence data from a set of related species and (2) design specific and degenerate primers for expression studies in the orphan crop of interest. To demonstrate the usability and reliability of the browser, it was used to identify the putative orthologues of 17 known lignin biosynthetic genes from maize and sugarcane in the orphan crop Miscanthus sinensis. Expression studies in miscanthus stem internode tissue differing in maturation were subsequently carried out, to follow the expression of these genes during lignification. Our results showed a negative correlation between lignin content and gene expression. The present data are in agreement with recent findings in maize and other crops, and it is further discussed in this paper. Electronic supplementary material The online version of this article (doi:10.1007/s11032-015-0430-2) contains supplementary material, which is available to authorized users.

Background and aims Arachis batizocoi is a wild relative of cultivated peanut (A. hypogaea), an allotetraploid with an AABB genome. Arachis batizocoi was once considered the ancestral donor of the peanut B genome, but cytogenetics and DNA phylogenies have indicated a new genome classification, 'K'. These observations seem inconsistent with genetic studies and breeding that have shown that A. batizocoi can behave as a B genome. Methods The genetic behaviour, genome composition and phylogenetic position of A. batizocoi were studied using controlled hybridizations, induced tetraploidy, whole-genome in situ fluorescent hybridization (GISH) and molecular phylogenetics. Key results Sterile diploid hybrids containing AK genomes were obtained using A. batizocoi and the A genome species A. duranensis, A. stenosperma, A. correntina or A. villosa. From these, three types of AAKK allotetraploids were obtained, each in multiple independent polyploidy events. Induced allotetraploids were vigorous and fertile, and were hybridized to A. hypogaea to produce F1 hybrids. Even with the same parental combination, fertility of these F1 hybrids varied greatly, suggesting the influence of stochastic genetic or epigenetic events. Interestingly, hybrids with A. hypogaea ssp. hypogaea were significantly more fertile than those with the subspecies fastigiata. GISH in cultivated × induced allotetraploids hybrids (harbouring AABK genomes) and a molecular phylogeny using 16 intron sequences showed that the K genome is distinct, but more closely related to the B than to the A genome. Conclusions The K genome of A. batizocoi is more related to B than to the A genome, but is distinct. As such, when incorporated in an induced allotetraploid (AAKK) it can behave as a B genome in crosses with peanut. However, the fertility of hybrids and their progeny depends upon the compatibility of the A genome interactions. The genetic distinctness of A. batizocoi makes it an important source of allelic diversity in itself, especially in crosses involving A. hypogaea ssp. hypogaea.

Most of the gene regulation pathways data from biochemical and molecular experiments are drawn from humans or from species commonly used as experimental animal models. Accordingly, the software packages to analyse these data on the basis of specific gene identification codes (IDs) or accession numbers (AN) are not easy to apply to other organisms that are less characterized at the genomic level. Here, we have developed the Gene2Path programme which automatically searches pathway databases to analyse microarray data in an independent, species-specific way. We have illustrated the method with data obtained from an immune targeted rainbow trout microarray to search for orthologous pathways defined for other well known biological species, such as zebrafish, although the software can be applied to any other case or species of interest. The scripts and programme are available and free at the “GENE2PATH” web site http://gene2path.no-ip.org/cgi-bin/gene2path/index.cgi. A user guide and examples are provided with the package. The Gene2Path software allows the automated searching of NCBI databases and the straightforward visualization of the data retrieved based on a graphic network environment., We thank Mario García-Lacoba for his advice and helpful comments. This work was funded by Consejo Superior de Investigaciones Cientificas (project 2010-20E084) and by Ministerio de Economia y Competitividad, (MINECO) project AGL2010- 18454 of Spain. N. Ballesteros wants to thank the MINECO for a PhD student fellowship

A gene order database of 32 completely sequenced plastid genomes was developed. The data structure is formally identical to that of the feature tables in the major GenBank/EMBL/DDBJ databases. The quality of annotations was largely improved. A normalizing gene-labeling system across the complete plastid genomes was developed so that comparative studies are made available without having to go back to sequence analysis. Many incorrect coordinates of tRNA-encoding regions found in the major databases were corrected. We attempted to distinctively label tRNA genes with the anticodon sequence CAT, which encodes either the initiator tRNA, elongator tRNA, or Ile-tRNA. The database is available at http://www.rs.noda.tus.ac.jp/~kunisawa.

Diatoms are among the most diverse groups of phytoplankton in the ocean. Despite their widely recognized influence on ocean ecosystems and global biogeochemistry, little is known about the impact of this diversity on large-scale processes. Here, we examined the ramifications of between-species diversity by documenting the transcriptional response of three diatoms —Thalassiosira pseudonana, Fragilariopsis cylindrus, and Pseudo-nitzschia multiseries —to the onset of nitrate limitation of growth, a common limiting nutrient in the ocean. The three species shared 5583 clusters of orthologous genes based on OrthoMCL clustering of publically available diatom genomes. These clusters represent 30–54% of the predicted genes in each diatom genome. Less than 5% of genes within these core clusters displayed the same transcriptional responses across species when growth was limited by nitrate availability. Orthologs, such as those involved in nitrogen uptake and assimilation, as well as carbon metabolism, were differently expressed across the three species. The two pennate diatoms, F. cylindrus and P. multiseries, shared 3839 clusters without orthologs in the genome of the centric diatom T. pseudonana. A majority of these pennate-clustered genes, as well as the non-orthologous genes in each species, had minimal annotation information, but were often significantly differentially expressed under nitrate limitation, indicating their potential importance in the response to nitrogen availability. Despite these variations in the specific transcriptional response of each diatom, overall transcriptional patterns suggested that all three diatoms displayed a common physiological response to nitrate limitation that consisted of a general reduction in carbon fixation and carbohydrate and fatty acid metabolism and an increase in nitrogen recycling. Characterization of these finely tuned responses will help to better predict which types of diatoms will bloom under which sets of environmental factors.

Background With genomic sequences of many closely related bacterial strains made available by deep sequencing, it is now possible to investigate trends in prokaryotic microevolution. Positive selection is a sub-process of microevolution, in which a particular mutation is favored, causing the allele frequency to continuously shift in one direction. Wide scanning of prokaryotic genomes has shown that positive selection at the molecular level is much more frequent than expected. Genes with significant positive selection may play key roles in bacterial adaption to different environmental pressures. However, selection pressure analyses are computationally intensive and awkward to configure. Results Here we describe an open access web server, which is designated as PSP (Positive Selection analysis for Prokaryotic genomes) for performing evolutionary analysis on orthologous coding genes, specially designed for rapid comparison of dozens of closely related prokaryotic genomes. Remarkably, PSP facilitates functional exploration at the multiple levels by assignments and enrichments of KO, GO or COG terms. To illustrate this user-friendly tool, we analyzed Escherichia coli and Bacillus cereus genomes and found that several genes, which play key roles in human infection and antibiotic resistance, show significant evidence of positive selection. PSP is freely available to all users without any login requirement at: http://db-mml.sjtu.edu.cn/PSP/. Conclusions PSP ultimately allows researchers to do genome-scale analysis for evolutionary selection across multiple prokaryotic genomes rapidly and easily, and identify the genes undergoing positive selection, which may play key roles in the interactions of host-pathogen and/or environmental adaptation.

Background Aspartic proteases (APs) are a large family of proteolytic enzymes found in almost all organisms. In plants, they are involved in many biological processes, such as senescence, stress responses, programmed cell death, and reproduction. Prior to the present study, no grape AP gene(s) had been reported, and their research on woody species was very limited. Results In this study, a total of 50 AP genes (VvAP) were identified in the grape genome, among which 30 contained the complete ASP domain. Synteny analysis within grape indicated that segmental and tandem duplication events contributed to the expansion of the grape AP family. Additional analysis between grape and Arabidopsis demonstrated that several grape AP genes were found in the corresponding syntenic blocks of Arabidopsis, suggesting that these genes arose before the divergence of grape and Arabidopsis. Phylogenetic relationships of the 30 VvAPs with the complete ASP domain and their Arabidopsis orthologs, as well as their gene and protein features were analyzed and their cellular localization was predicted. Moreover, expression profiles of VvAP genes in six different tissues were determined, and their transcript abundance under various stresses and hormone treatments were measured. Twenty-seven VvAP genes were expressed in at least one of the six tissues examined; nineteen VvAPs responded to at least one abiotic stress, 12 VvAPs responded to powdery mildew infection, and most of the VvAPs responded to SA and ABA treatments. Furthermore, integrated synteny and phylogenetic analysis identified orthologous AP genes between grape and Arabidopsis, providing a unique starting point for investigating the function of grape AP genes. Conclusions The genome-wide identification, evolutionary and expression analyses of grape AP genes provide a framework for future analysis of AP genes in defining their roles during stress response. Integrated synteny and phylogenetic analyses provide novel insight into the functions of less well-studied genes using information from their better understood orthologs.

The relationship between genome characteristics and several human diseases has been a central research goal in genomics. Many studies have shown that specific gene patterns, such as amino acid repetitions, are associated with human diseases. However, several open questions still remain, such as, how these tandem repeats appeared in the evolutionary path or how they have evolved in orthologous genes of related organisms. In this paper, we present a computational solution that facilitates comparative studies of orthologous genes from various organisms. The application uses various web services to gather gene sequence information, local algorithms for tandem repeats identification and similarity measures for gene clustering. published

Background A genome-wide comparative analysis of human and mouse gene expression patterns was performed in order to evaluate the evolutionary divergence of mammalian gene expression. Tissue-specific expression profiles were analyzed for 9,105 human-mouse orthologous gene pairs across 28 tissues. Expression profiles were resolved into species-specific coexpression networks, and the topological properties of the networks were compared between species. Results At the global level, the topological properties of the human and mouse gene coexpression networks are, essentially, identical. For instance, both networks have topologies with small-world and scale-free properties as well as closely similar average node degrees, clustering coefficients, and path lengths. However, the human and mouse coexpression networks are highly divergent at the local level: only a small fraction ( Conclusion The dissonance between global versus local network divergence suggests that the interspecies similarity of the global network properties is of limited biological significance, at best, and that the biologically relevant aspects of the architectures of gene coexpression are specific and particular, rather than universal. Nevertheless, there is substantial evolutionary conservation of the local network structure which is compatible with the notion that gene coexpression networks are subject to purifying selection.

Finding orthologous genes among multiple sequenced genomes is a primary step in comparative genomics studies. With the number of sequenced genomes increasing exponentially, comparative genomics becomes more powerful than ever for genomic analysis. However, the very large number of genomes in need of analysis makes conventional orthology prediction methods incapable of this task. Thus, an ultrafast tool is urgently needed. Here, we present PorthoMCL, a fast tool for finding orthologous genes among a very large number of genomes. PorthoMCL can be run on a single machine or in parallel on computer clusters. We have demonstrated PorthoMCL’s capability by identifying orthologs in 2,758 prokaryotic genomes. The results are available for download at: http://ehsun.me/go/porthomcl/ . PorthoMCL is a fast and easy to run tool for identifying orthology among any number of genomes with minimal requirements. PorthoMCL will facilitate comparative genomics analysis with increasing number of available genomes thanks to the rapidly evolving sequencing technologies.