Phylogenomics

Chloroplast genomes of plants are highly conserved in both gene order and gene content, are maternally inherited, and have a lower rate of evolution. Chloroplast genomes are considered to be good models for testing lineage-specific molecular evolution. In this study, we use Schisandraceae as an example to generate insights into the overall evolutionary dynamics in chloroplast genomes and to establish the phylogenetic relationship of Schisandraceae based on chloroplast genome data using phylogenomic analysis...

BACKGROUND: Translation of specific mRNAs can be highly regulated in different cells, tissues or under pathological conditions. Ribosome heterogeneity can originate from variable expression or post-translational modifications of ribosomal proteins. The ribosomal oxygenases RIOX1 (NO66) and RIOX2 (MINA53) modify ribosomal proteins by histidine hydroxylation. A similar mechanism is present in prokaryotes. Thus, ribosome hydroxylation may be a well-conserved regulatory mechanism with implications in disease and development...

BACKGROUND: Some mobile genetic elements target the lagging strand template during DNA replication. Bacterial examples are insertion sequences IS608 and ISDra2 (IS200/IS605 family members). They use obligatory single-stranded circular DNA intermediates for excision and insertion and encode a transposase, TnpAIS200 , which recognizes subterminal secondary structures at the insertion sequence ends. Similar secondary structures, Repeated Extragenic Palindromes (REP), are present in many bacterial genomes...

Summary: The exploration and comparison of genome organization is routinely used in the frame of genomic and phylogenomic analyses. As a consequence, in the past few years, various tools allowing visualizing genomic contexts have been developed. However, their use is often hampered by a lack of flexibility, particularly concerning databases, input formats and figure customization. Here we present GeneSpy, a graphical user interface that allows the visualization and dynamic exploration of eukaryotic and prokaryotic annotated genomes...

Ciliates are one of the eukaryotic unicellular organisms which are thought to be the oldest life forms, and widely geographically distributed. For a variety of reasons, some groups of ciliates have attracted more attention than others, such as the class Spirotrichea and related species with its complicated evolutionary relationships. In this study, we obtained the transcriptome data of three typical ciliates, Uroleptopsis citrina, Euplotes vannus, Protocruzia tuzeti using high throughput sequencing. The genetic relationships were revealed by phylogenomic analysis of 109 genes comprising of 34,882 amino acid residues, and analyses based on SSU rDNA of 55 species, as well as the comparison of gene content among spirotricheans and related species...

Type III secretion system effectors contribute to pathogenicity through various mechanisms. Recent surveys showed an increasing prevalence of the type III secretion effector, avrBsT, among Xanthomonas perforans (Xp). We hypothesized that the acquisition of avrBsT has a fitness advantage for the pathogen. The contribution of avrBsT to fitness on tomato was evaluated based on disease severity, in planta growth, competition and recovery rates of wild-type (WT) and avrBsT mutant strains in greenhouse and field plants...

We present a genomic data set comprised of the coding DNA sequences of 5162 loci from 90 vertebrate species, including 82 mammals. The loci were aligned with their protein sequences. The aligned protein sequences were then back translated into their original DNA sequences. The alignments were further filtered to remove individual sequences from each alignment exhibiting long branches or other unusual features. The data is deposited in figshare (http://figshare.com/articles/cds_5162.zip/6031190) and will be useful as a test data set for large-scale phylogenomic analysis...

The deep history and early diversification of retroviruses remains elusive, largely because few retroviruses have been characterized in vertebrates other than mammals and birds. Endogenous retroviruses (ERVs) documented past retroviral infections and thus provide 'molecular fossils' for studying the deep history of retroviruses. Here we perform a comprehensive phylogenomic analysis of ERVs within the genomes of 92 non-avian/mammalian vertebrates, including 72 fishes, 4 amphibians, and 16 reptiles. We find that ERVs are present in all the genomes of jawed vertebrates, revealing the ubiquitous presence of ERVs in jawed vertebrates...

Serratia marcescens is an environmental bacterium commonly associated with outbreaks in neonatal intensive care units (NICU). Investigation of S. marcescens outbreaks requires efficient recovery and typing of clinical and environmental isolates. In this study, we described how the use of next-generation sequencing applications, such as bacterial whole-genome sequencing (WGS) and bacterial community profiling, could improve S. marcescens outbreak investigation. Phylogenomic links and potential antibiotic resistance genes and plasmids in S...

Simian retrovirus (SRV) is a type-D betaretrovirus infectious to the Old World monkeys causing a variety of symptoms. SRVs are also present in the Old World monkey genomes as endogenous forms, which are referred to as Simian endogenous retroviruses (SERVs). Although many SERV sequences have been identified in Cercopithecinae genomes, with potential of encoding all functional genes, the distribution of SERVs in genomes and evolutionary relationship between exogeneous SRVs and SERVs remains unclear. In this study, we comprehensively investigated seven draft genome sequences of the Old World monkeys, and identified a novel cluster of SERVs in the two Rhinopithecus (R...

Recent studies have demonstrated that conflict is common among gene trees in phylogenomic studies, and that less than one percent of genes may ultimately drive species tree inference in supermatrix analyses. Here, we examined two datasets where supermatrix and coalescent-based species trees conflict. We identified two highly influential "outlier" genes in each dataset. When removed from each dataset, the inferred supermatrix trees matched the topologies obtained from coalescent analyses. We also demonstrate that, while the outlier genes in the vertebrate dataset have been shown in a previous study to be the result of errors in orthology detection, the outlier genes from a plant dataset did not exhibit any obvious systematic error and therefore may be the result of some biological process yet to be determined...

In this study, the chloroplast genome of Hariotina reticulata was fully sequenced and compared to other Sphaeropleales chloroplast genomes. It is 210,757 bp larger than most Sphaeropleales cpDNAs. It presents a traditional chloroplast structure, and contains 103 genes, including 68 protein-coding genes, six rRNA genes and 29 tRNA genes. The coding region constitutes of 43% of the whole cpDNA. Eighteen introns are found in 11 genes and six introns are unique for Hariotina. 11 open reading frames are identified among these introns...

The appearance of multicellular animals during the Neoproterozoic Era is thought to have coincided with oxygenation of the oceans, however we know little about the physiological needs of early animals or about the environment they lived in. Approaches using biomarkers, fossils, and phylogenomics have provided some hints of the types of animals that may have been present during the Neoproterozoic, but extant animals are our best modern links to the theoretical ancestors of animals. Neoproterozoic oceans were low energy habitats, with low oxygen concentrations and sparse food availability for the first animals...

Phylogenetic relationships within the green algal phylum Chlorophyta have proven difficult to resolve. The core Chlorophyta include Chlorophyceae, Ulvophyceae, Trebouxiophyceae, Pedinophyceae and Chlorodendrophyceae, but the relationships among these classes remain unresolved and the monophyly of Ulvophyceae and Trebouxiophyceae are highly controversial. We analyzed a dataset of 101 green algal species and 73 protein-coding genes sampled from complete and partial chloroplast genomes, including six newly sequenced ulvophyte genomes (Blidingia minima NIES-1837, Ulothrix zonata, Halochlorococcum sp...

Massive strides have been made in technologies for collecting genome-scale data. However, tools for efficiently and flexibly assembling raw outputs into downstream analytical workflows are still nascent. aTRAM 1.0 was designed to assemble any locus from genome sequencing data but was neither optimized for efficiency nor able to serve as a single toolkit for all assembly needs. We have completely re-implemented aTRAM and redesigned its structure for faster read retrieval while adding a number of key features to improve flexibility and functionality...

BACKGROUND: Porous species boundaries can be a source of conflicting hypotheses, particularly when coupled with variable data and/or methodological approaches. Their impacts can often be magnified when non-model organisms with complex histories of reticulation are investigated. One such example is the genus Catostomus (Osteichthys, Catostomidae), a freshwater fish clade with conflicting morphological and mitochondrial phylogenies. The former is hypothesized as reflecting the presence of admixed genotypes within morphologically distinct lineages, whereas the latter is interpreted as the presence of distinct morphologies that emerged multiple times through convergent evolution...

Phylogenomics aims to infer the evolutionary relationships of organisms, and their genomes, genes, and proteins, from genomic data. Understanding the evolution of these components can provide clues about their biological functions. Here we describe minimal protocols for inferring families of genes (and the proteins they encode), and using them in phylogenomic analyses to infer species trees.

Molecular phylogenetics has transitioned into the phylogenomic era, with data derived from next-generation sequencing technologies allowing unprecedented phylogenetic resolution in all animal groups, including understudied invertebrate taxa. Within the most diverse harvestmen suborder, Laniatores, most relationships at all taxonomic levels have yet to be explored from a phylogenomics perspective. Travunioidea is an early-diverging lineage of laniatorean harvestmen with a Laurasian distribution, with species distributed in eastern Asia, eastern and western North America, and south-central Europe...

Two moderately psychrophilic actinobacterial strains, designated AU-G6T and AU-A3.2, isolated from the surface of an Antarctic macroalga, Adenocystis utricularis (Bory) Skottsberg, was taxonomically characterized based on a polyphasic investigation. The two strains had nearly identical 16S rRNA gene sequences and formed a distinct phyletic line within the genus Amycolatopsis of the family Pseudonocardiaceae. They were phylogenetically close to Amycolatopsis nigrescens JCM 14717T , Amycolatopsis minnesotensis JCM 14545T and Amycolatopsis magusensis DSM 45510T , with 16S rRNA gene sequence similarities of 97...

Summary: Phylogenomic datasets invariably contain undetected stretches of non-homologous characters due to poor-quality sequences or erroneous gene models. The large-scale multigene nature of these datasets renders impractical or impossible detailed manual curation of sequences, but few tools exist that can automate this task. To address this issue, we developed a new method that takes as input a set of unaligned homologous sequences and uses an explicit probabilistic approach to identify and mask regions with non-homologous adjacent characters...