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Biomedical subjects

J Tamames

Publications and source records attributed to J Tamames.

7 recordsLinked to original sources
PubMed1998

EUCLID: automatic classification of proteins in functional classes by their database annotations.

UNLABELLED: A tool is described for the automatic classification of sequences in functional classes using their database annotations. The Euclid system is based on a simple learning procedure from examples provided by human experts. AVAILABILITY: Euclid is freely available for academics at http://www.gredos.cnb.uam.es/EUCLID, with the corresponding dictionaries for the generation of three, eight and 14 functional classes. CONTACT: E-mail: valencia@cnb.uam.es SUPPLEMENTARY INFORMATION: The results of the EUCLID classification of different genomes are available at http://www.sander.ebi.ac. uk/genequiz/. A detailed description of the different applications mentioned in the text is available at http://www.gredos.cnb.uam. es/EUCLID/Full_Paper

Computational Biology↗
PubMed1997

Conserved clusters of functionally related genes in two bacterial genomes.

An approach for genome comparison, combining function classification of gene products and sequence comparison, is presented. The genomes of Haemophilus influenzae and Escherichia coli are analyzed, and all genes are classified into nine major functional classes, corresponding to important cellular processes. To study gene order relationships and genome organization in the two bacteria, we performed statistics on neighboring pairs of genes. To estimate the significance of the observations, a statistical model based on binomial distributions has been developed. Significant patterns of gene order are observed within, as well as between, the two bacterial genomes: Functionally related genes tend to be neighbors more often than do unrelated genes. Some of these groups represent well-known operons, but additional gene clusters are identified. These clusters correspond to genomic elements that have been conserved during bacterial evolution. In addition to nearest-neighbor relationships, the method is also useful to study the relative direction of transcription in genomes, which is also highly conserved between homologous gene pairs. This new approach combines the high-level description of molecular function with pair statistics that express genome organization. It is expected to complement traditional methods of sequence analysis in the study of genomic structure, function, and evolution.

Binomial Distribution↗
PubMed1996

Genomes with distinct function composition.

The functional composition of organisms can be analysed for the first time with the appearance of complete or sizeable parts of various genomes. We have reduced the problem of protein function classification to a simple scheme with three classes of protein function: energy-, information- and communication-associated proteins. Finer classification schemes can be easily mapped to the above three classes. To deal with the vast amount of information, a system for automatic function classification using database annotations has been developed. The system is able to classify correctly about 80% of the query sequences with annotations. Using this system, we can analyse samples from the genomes of the most represented species in sequence databases and compare their genomic composition. The similarities and differences for different taxonomic groups are strikingly intuitive. Viruses have the highest proportion of proteins involved in the control and expression of genetic information. Bacteria have the highest proportion of their genes dedicated to the production of proteins associated with small molecule transformations and transport. Animals have a very large proportion of proteins associated with intra- and intercellular communication and other regulatory processes. In general, the proportion of communication-related proteins increases during evolution, indicating trends that led to the emergence of the eukaryotic cell and later the transition from unicellular to multicellular organisms.

Animals↗
PubMed1996

Computational comparisons of model genomes.

Complete genomes from model organisms provide new challenges for computational molecular biology. Novel questions emerge from the genome data obtained from the functional prediction of thousands of gene products. In this review, we present some approaches to the computational comparison of genomes, based on sequence and text analysis, and comparisons of genome composition and gene order.

Biotechnology↗
PubMed1995

Nucleotide sequence and analysis of the centromeric region of yeast chromosome IX.

We have determined the nucleotide sequence of a cosmid (pIX338) containing the centromere region of yeast (Saccharomyces cerevisiae) chromosome IX. The complete nucleotide sequence of 33.8 kb was obtained by using an efficient directed sequencing strategy in combination with automated DNA sequencing on the A.L.F. DNA sequencer. Sequence analysis revealed the presence of 17 open reading frames (ORFs), four of them previously known yeast genes (sly12, pan1, sts1 and prl1), a tRNA gene and the centromere motif. Exhaustive database searches detected sequence homologues of known function for as many as 14 of the 17 ORFs. These include a mammalian tyrosine kinase substrate; the Escherichia coli cell cycle protein MinD; the human inositol polyphosphate-5-phosphatase (gene OCRL) involved in Lowe's syndrome, a developmental disorder; and helicases, for which the new yeast member defines a distinct DEAD/H-box subfamily. A surprisingly large fraction of the ORFs (at least six out of 17) in the centromeric region are apparently involved in RNA or DNA binding.

Adenosine Triphosphatases↗