Author Archives: Rui Lebre

Smash is a completely alignment-free method/tool to find and visualise genomic rearrangements. The detection is based on conditional exclusive compression, namely using a FCM (Markov model), of high context order (typically 20). For visualisation, Smash outputs a SVG image, with an ideogram output architecture, where the patterns are represented with several HSV values. It can perform both in small- and large-scale.

EAGLE is an alignment-free method and associated program to compute relative absent words (RAW) in genomic sequences using a reference sequence. Currently, EAGLE runs on a command line linux environment, building an image with patterns reporting the absent words regions (in SVG) as well as reporting the associated positions into a file. EAGLE hast got scripts to run on the current outbreak 99 ebola virus genomes (using the human as a reference), including the download, filtering and processing of the entire data.

MENT is a set of tools for lossless compression of microarray images. These tools can also be used for other types of images such as medical, RNAi, etc. This set of tools are divided into two categories. One where a bitplane decomposition approach is used and the other one where a binary tree decomposition is used.

XS is a skilled FASTQ read simulation tool, flexible, portable (does not need a reference sequence) and tunable in terms of sequence complexity. It has several running modes, depending on the time and memory available, and is aimed at testing computing infrastructures, namely cloud computing of large-scale projects, and testing FASTQ compression algorithms. Moreover, XS offers the possibility of simulating the three main FASTQ components individually (headers, DNA sequences and quality-scores)

SACO is a method to handle the DNA bases and gap symbols that can be found in MAF files. SACO is based on a mixture of finite-context models. Contrarily Hanus et al approach, it addresses both the DNA bases and gap symbols at once, better exploring the existing correlations. For comparison with previous methods, our algorithm was tested in the multiz28way dataset. On average, it attained 0.94 bits per symbol, approximately 7% better than the previous best, for a similar computational complexity.

MAFCO is a lossless compression tool specifically designed to compress MAF (Multiple Alignment Format) files. Compared to gzip, the proposed tool attains a compression gain from ≈ 34% to ≈ 57%, depending on the data set. When compared to a recent dedicated method, which is not compatible with some data sets, the compression gain of MAFCO is about 9%.

Machine learning system to classify metagenomic samples.

DNAatGlance is a program for the detection of large-scale genomic regularities by visual inspection. Several discovery strategies are possible, including the standalone analysis of single sequences, the comparative analysis of sequences from individuals from the same species, and the comparative analysis of sequences from different organisms.

MFCompress is a compression tool for FASTA and multi-FASTA files. In comparison to gzip and applied to multi-FASTA files, MFCompress can provide additional average compression gains of almost 50%, i.e., it potentially doubles the available storage, although at the cost of some more computation time. On highly redundant data sets, and in comparison with gzip, 8-fold size reductions have been obtained.