Articles

A graph extension of the positional Burrows–Wheeler transform and its applications

We present a generalization of the positional Burrows–Wheeler transform, or PBWT, to genome graphs, which we call the gPBWT. A genome graph is a collapsed representation of a set of genomes described as a grap...

Authors: Adam M. Novak, Erik Garrison and Benedict Paten

Isometric gene tree reconciliation revisited

Isometric gene tree reconciliation is a gene tree/species tree reconciliation problem where both the gene tree and the species tree include branch lengths, and these branch lengths must be respected by the rec...

Authors: Broňa Brejová, Askar Gafurov, Dana Pardubská, Michal Sabo and Tomáš Vinař

Algorithms for computing the double cut and join distance on both gene order and intergenic sizes

Combinatorial works on genome rearrangements have so far ignored the influence of intergene sizes, i.e. the number of nucleotides between consecutive genes, although it was recently shown decisive for the accu...

Authors: Guillaume Fertin, Géraldine Jean and Eric Tannier

StreAM-\(T_g\): algorithms for analyzing coarse grained RNA dynamics based on Markov models of connectivity-graphs

In this work, we present a new coarse grained representation of RNA dynamics. It is based on adjacency matrices and their interactions patterns obtained from molecular dynamics simulations. RNA molecules are w...

Authors: Sven Jager, Benjamin Schiller, Philipp Babel, Malte Blumenroth, Thorsten Strufe and Kay Hamacher

The gene family-free median of three

The gene family-free framework for comparative genomics aims at providing methods for gene order analysis that do not require prior gene family assignment, but work directly on a sequence similarity graph. We ...

Authors: Daniel Doerr, Metin Balaban, Pedro Feijão and Cedric Chauve

Complexity and algorithms for copy-number evolution problems

Cancer is an evolutionary process characterized by the accumulation of somatic mutations in a population of cells that form a tumor. One frequent type of mutations is copy number aberrations, which alter the n...

Authors: Mohammed El-Kebir, Benjamin J. Raphael, Ron Shamir, Roded Sharan, Simone Zaccaria, Meirav Zehavi and Ron Zeira

A better scoring model for de novo peptide sequencing: the symmetric difference between explained and measured masses

Given a peptide as a string of amino acids, the masses of all its prefixes and suffixes can be found by a trivial linear scan through the amino acid masses. The inverse problem is the ideal ...

Authors: Thomas Tschager, Simon Rösch, Ludovic Gillet and Peter Widmayer

Core column prediction for protein multiple sequence alignments

In a computed protein multiple sequence alignment, the coreness of a column is the fraction of its substitutions that are in so-called core columns of the gold-standard reference alignment of its proteins. In ben...

Authors: Dan DeBlasio and John Kececioglu

Aligning coding sequences with frameshift extension penalties

Frameshift translation is an important phenomenon that contributes to the appearance of novel coding DNA sequences (CDS) and functions in gene evolution, by allowing alternative amino acid translations of gene...

Authors: Safa Jammali, Esaie Kuitche, Ayoub Rachati, François Bélanger, Michelle Scott and Aïda Ouangraoua

Gerbil: a fast and memory-efficient k-mer counter with GPU-support

A basic task in bioinformatics is the counting of k-mers in genome sequences. Existing k-mer counting tools are most often optimized for small k < 32 and suffer from excessive memory resource consumption or degra...

Authors: Marius Erbert, Steffen Rechner and Matthias Müller-Hannemann

The feasibility of genome-scale biological network inference using Graphics Processing Units

Systems research spanning fields from biology to finance involves the identification of models to represent the underpinnings of complex systems. Formal approaches for data-driven identification of network int...

Authors: Raghuram Thiagarajan, Amir Alavi, Jagdeep T. Podichetty, Jason N. Bazil and Daniel A. Beard

An efficient algorithm for testing the compatibility of phylogenies with nested taxa

Semi-labeled trees generalize ordinary phylogenetic trees, allowing internal nodes to be labeled by higher-order taxa. Taxonomies are examples of semi-labeled trees. Suppose we are given collection

Authors: Yun Deng and David Fernández-Baca

On the computational complexity of the maximum parsimony reconciliation problem in the duplication-loss-coalescence model

Phylogenetic tree reconciliation is a widely-used method for inferring the evolutionary histories of genes and species. In the duplication-loss-coalescence (DLC) model, we seek a reconciliation that explains t...

Authors: Daniel Bork, Ricson Cheng, Jincheng Wang, Jean Sung and Ran Libeskind-Hadas

On avoided words, absent words, and their application to biological sequence analysis

The deviation of the observed frequency of a word w from its expected frequency in a given sequence x is used to determine whether or not the word is avoided. This concept is particularly useful in DNA linguisti...

Authors: Yannis Almirantis, Panagiotis Charalampopoulos, Jia Gao, Costas S. Iliopoulos, Manal Mohamed, Solon P. Pissis and Dimitris Polychronopoulos

Approximating the correction of weighted and unweighted orthology and paralogy relations

Given a gene family, the relations between genes (orthology/paralogy), are represented by a relation graph, where edges connect pairs of orthologous genes and “missing” edges represent paralogs. While a gene t...

Authors: Riccardo Dondi, Manuel Lafond and Nadia El-Mabrouk

Approximating the DCJ distance of balanced genomes in linear time

Rearrangements are large-scale mutations in genomes, responsible for complex changes and structural variations. Most rearrangements that modify the organization of a genome can be represented by the double cut...

Authors: Diego P. Rubert, Pedro Feijão, Marília Dias Vieira Braga, Jens Stoye and Fábio Henrique Viduani Martinez

Playing hide and seek with repeats in local and global de novo transcriptome assembly of short RNA-seq reads

The main challenge in de novo genome assembly of DNA-seq data is certainly to deal with repeats that are longer than the reads. In de novo transcriptome assembly of RNA-seq reads, on the other hand, this prob...

Authors: Leandro Lima, Blerina Sinaimeri, Gustavo Sacomoto, Helene Lopez-Maestre, Camille Marchet, Vincent Miele, Marie-France Sagot and Vincent Lacroix

Best hits of 11110110111: model-free selection and parameter-free sensitivity calculation of spaced seeds

Spaced seeds, also named gapped q-grams, gapped k-mers, spaced q-grams, have been proven to be more sensitive than contiguous seeds (contiguous q-grams, contiguous k-mers) in nucleic a...

Authors: Laurent Noé

Erratum to: A representation of a compressed de Bruijn graph for pan-genome analysis that enables search

Authors: Timo Beller and Enno Ohlebusch

An efficient algorithm for protein structure comparison using elastic shape analysis

Protein structure comparison play important role in in silico functional prediction of a new protein. It is also used for understanding the evolutionary relationships among proteins. A variety of methods have ...

Authors: S. Srivastava, S. B. Lal, D. C. Mishra, U. B. Angadi, K. K. Chaturvedi, S. N. Rai and A. Rai

Analysis of gene copy number changes in tumor phylogenetics

Evolution of cancer cells is characterized by large scale and rapid changes in the chromosomal  landscape. The fluorescence in situ hybridization (FISH) technique provides a way to measure the copy numbers of ...

Authors: Jun Zhou, Yu Lin, Vaibhav Rajan, William Hoskins, Bing Feng and Jijun Tang

Enumeration of minimal stoichiometric precursor sets in metabolic networks

What an organism needs at least from its environment to produce a set of metabolites, e.g. target(s) of interest and/or biomass, has been called a minimal precursor set. Early approaches to enumerate all minimal ...

Authors: Ricardo Andrade, Martin Wannagat, Cecilia C. Klein, Vicente Acuña, Alberto Marchetti-Spaccamela, Paulo V. Milreu, Leen Stougie and Marie-France Sagot

Using a constraint-based regression method for relative quantification of somatic mutations in pyrosequencing signals: a case for NRAS analysis

Pyrosequencing Allele Quantification (AQ) is a cost-effective DNA sequencing method that can be used for detecting somatic mutations in formalin-fixed paraffin-embedded (FFPE) samples. The method displays a lo...

Authors: Jerome Ambroise, Jamal Badir, Louise Nienhaus, Annie Robert, Anne-France Dekairelle and Jean-Luc Gala

BiC2PAM: constraint-guided biclustering for biological data analysis with domain knowledge

Biclustering has been largely used in biological data analysis, enabling the discovery of putative functional modules from omic and network data. Despite the recognized importance of incorporating domain knowl...

Authors: Rui Henriques and Sara C. Madeira

An improved Four-Russians method and sparsified Four-Russians algorithm for RNA folding

The basic RNA secondary structure prediction problem or single sequence folding problem (SSF) was solved 35 years ago by a now well-known

Authors: Yelena Frid and Dan Gusfield

Erratum to: Circular sequence comparison: algorithms and applications

Authors: Roberto Grossi, Costas S. Iliopoulos, Robert Mercas, Nadia Pisanti, Solon P. Pissis, Ahmad Retha and Fatima Vayani

A representation of a compressed de Bruijn graph for pan-genome analysis that enables search

Recently, Marcus et al. (Bioinformatics 30:3476–83, 2014) proposed to use a compressed de Bruijn graph to describe the relationship between the genomes of many individuals/strains of the same or closely related s...

Authors: Timo Beller and Enno Ohlebusch

A Bayesian inference method for the analysis of transcriptional regulatory networks in metagenomic data

Metagenomics enables the analysis of bacterial population composition and the study of emergent population features, such as shared metabolic pathways. Recently, we have shown that metagenomics datasets can be...

Authors: Elizabeth T. Hobbs, Talmo Pereira, Patrick K. O’Neill and Ivan Erill

An effective sequence-alignment-free superpositioning of pairwise or multiple structures with missing data

Superpositioning is an important problem in structural biology. Determining an optimal superposition requires a one-to-one correspondence between the atoms of two proteins structures. However, in practice, som...

Authors: Jianbo Lu, Guoliang Xu, Shihua Zhang and Benzhuo Lu

An algorithm to parse segment packing in predicted protein contact maps

The analysis of correlation in alignments generates a matrix of predicted contacts between positions in the structure and while these can arise for many reasons, the simplest explanation is that the pair of re...

Authors: William R. Taylor

Identification of donor splice sites using support vector machine: a computational approach based on positional, compositional and dependency features

Identification of splice sites is essential for annotation of genes. Though existing approaches have achieved an acceptable level of accuracy, still there is a need for further improvement. Besides, most of th...

Authors: Prabina Kumar Meher, Tanmaya Kumar Sahu, A. R. Rao and S. D. Wahi

Towards sub-quadratic time and space complexity solutions for the dated tree reconciliation problem

Recent coevolutionary analysis has considered tree topology as a means to reduce the asymptotic complexity associated with inferring the complex coevolutionary interrelationships that arise between phylogeneti...

Authors: Benjamin Drinkwater and Michael A. Charleston

BicNET: Flexible module discovery in large-scale biological networks using biclustering

Despite the recognized importance of module discovery in biological networks to enhance our understanding of complex biological systems, existing methods generally suffer from two major drawbacks. First, there...

Authors: Rui Henriques and Sara C. Madeira

Models and algorithms for genome rearrangement with positional constraints

Traditionally, the merit of a rearrangement scenario between two gene orders has been measured based on a parsimony criteria alone; two scenarios with the same number of rearrangements are considered equally g...

Authors: Krister M. Swenson, Pijus Simonaitis and Mathieu Blanchette

Circular sequence comparison: algorithms and applications

Sequence comparison is a fundamental step in many important tasks in bioinformatics; from phylogenetic reconstruction to the reconstruction of genomes. Traditional algorithms for measuring approximation in seq...

Authors: Roberto Grossi, Costas S. Iliopoulos, Robert Mercas, Nadia Pisanti, Solon P. Pissis, Ahmad Retha and Fatima Vayani

An exact algorithm for finding cancer driver somatic genome alterations: the weighted mutually exclusive maximum set cover problem

The mutual exclusivity of somatic genome alterations (SGAs), such as somatic mutations and copy number alterations, is an important observation of tumors and is widely used to search for cancer signaling pathw...

Authors: Songjian Lu, Gunasheil Mandava, Gaibo Yan and Xinghua Lu

Jabba: hybrid error correction for long sequencing reads

Third generation sequencing platforms produce longer reads with higher error rates than second generation technologies. While the improved read length can provide useful information for downstream analysis, un...

Authors: Giles Miclotte, Mahdi Heydari, Piet Demeester, Stephane Rombauts, Yves Van de Peer, Pieter Audenaert and Jan Fostier

Bitpacking techniques for indexing genomes: II. Enhanced suffix arrays

Suffix arrays and their variants are used widely for representing genomes in search applications. Enhanced suffix arrays (ESAs) provide fast search speed, but require large auxiliary data structures for storin...

Authors: Thomas D. Wu

RNA folding with hard and soft constraints

A large class of RNA secondary structure prediction programs uses an elaborate energy model grounded in extensive thermodynamic measurements and exact dynamic programming algorithms. External experimental evid...

Authors: Ronny Lorenz, Ivo L. Hofacker and Peter F. Stadler

Sparse RNA folding revisited: space-efficient minimum free energy structure prediction

RNA secondary structure prediction by energy minimization is the central computational tool for the analysis of structural non-coding RNAs and their interactions. Sparsification has been successfully applied to i...

Authors: Sebastian Will and Hosna Jabbari

MissMax: alignment-free sequence comparison with mismatches through filtering and heuristics

Measuring sequence similarity is central for many problems in bioinformatics. In several contexts alignment-free techniques based on exact occurrences of substrings are faster, but also less accurate, than ali...

Authors: Cinzia Pizzi

Bitpacking techniques for indexing genomes: I. Hash tables

Hash tables constitute a widely used data structure for indexing genomes that provides a list of genomic positions for each possible oligomer of a given size. The offset array in a hash table grows exponential...

Authors: Thomas D. Wu

The link between orthology relations and gene trees: a correction perspective

While tree-oriented methods for inferring orthology and paralogy relations between genes are based on reconciling a gene tree with a species tree, many tree-free methods are also available (usually based on se...

Authors: Manuel Lafond, Riccardo Dondi and Nadia El-Mabrouk

Bloom Filter Trie: an alignment-free and reference-free data structure for pan-genome storage

High throughput sequencing technologies have become fast and cheap in the past years. As a result, large-scale projects started to sequence tens to several thousands of genomes per species, producing a high nu...

Authors: Guillaume Holley, Roland Wittler and Jens Stoye

Estimation of genetic diversity in viral populations from next generation sequencing data with extremely deep coverage

In this paper we propose a method and discuss its computational implementation as an integrated tool for the analysis of viral genetic diversity on data generated by high-throughput sequencing. The main motiva...

Authors: Jean P. Zukurov, Sieberth do Nascimento-Brito, Angela C. Volpini, Guilherme C. Oliveira, Luiz Mario R. Janini and Fernando Antoneli

The paralog-to-contig assignment problem: high quality gene models from fragmented assemblies

The accurate annotation of genes in newly sequenced genomes remains a challenge. Although sophisticated comparative pipelines are available, computationally derived gene models are often less than perfect. Thi...

Authors: Henrike Indrischek, Nicolas Wieseke, Peter F. Stadler and Sonja J. Prohaska

Interpretation and approximation tools for big, dense Markov chain transition matrices in population genetics

Markov chains are a common framework for individual-based state and time discrete models in evolution. Though they played an important role in the development of basic population genetic theory, the analysis o...

Authors: Katja Reichel, Valentin Bahier, Cédric Midoux, Nicolas Parisey, Jean-Pierre Masson and Solenn Stoeckel

HIA: a genome mapper using hybrid index-based sequence alignment

A number of alignment tools have been developed to align sequencing reads to the human reference genome. The scale of information from next-generation sequencing (NGS) experiments, however, is increasing rapid...

Authors: Jongpill Choi, Kiejung Park, Seong Beom Cho and Myungguen Chung

Designing minimal microbial strains of desired functionality using a genetic algorithm

The rational, in silico prediction of gene-knockouts to turn organisms into efficient cell factories is an essential and computationally challenging task in metabolic engineering. Elementary flux mode analys...

Authors: Govind Nair, Christian Jungreuthmayer, Michael Hanscho and Jürgen Zanghellini

A reconstruction problem for a class of phylogenetic networks with lateral gene transfers

Lateral, or Horizontal, Gene Transfers are a type of asymmetric evolutionary events where genetic material is transferred from one species to another. In this paper we consider LGT networks, a general model of p...

Authors: Gabriel Cardona, Joan Carles Pons and Francesc Rosselló