PubMed Health⌕ Search

Biomedical subjects

S Liuni

Publications and source records attributed to S Liuni.

6 recordsLinked to original sources
PubMed1992

WORDUP: an efficient algorithm for discovering statistically significant patterns in DNA sequences.

We present here a fast and sensitive method designed to isolate short nucleotide sequences which have non-random statistical properties and may thus be biologically active. It is based on a first order Markov analysis and allows us to detect statistically significant sequence motifs from six to ten nucleotides long which are significantly shared (or avoided) in the sequences under investigation. This method has been tested on a set of 521 sequences extracted from the Eukaryotic Promoter Database (2). Our results demonstrate the accuracy and the efficiency of the method in that the sequence motifs which are known to act as eukaryotic promoters, such as the TATA-box and the CAAT-box, were clearly identified. In addition we have found other statistically significant motifs, the biological roles of which are yet to be clarified.

Algorithms↗
PubMed1992

A simple method for global sequence comparison.

A simple method of sequence comparison, based on a correlation analysis of oligonucleotide frequency distributions, is here shown to be a reliable test of overall sequence similarity. The method does not involve sequence alignment procedures and permits the rapid screening of large amounts of sequence data. It identifies those sequences which deserve more careful analysis of sequence similarity at the level of resolution of the single nucleotide. It uses observed quantities only and does not involve the adoption of any theoretical model.

Algorithms↗
PubMed1990

Detection of latent sequence periodicities.

A method is proposed for the automatic detection of serial periodicities in a linear sequence. Its application to DNA subtelomeric sequences from two lower eukaryotes, P.falciparum and S.cerevisiae, reveals ordered patterns organised in hierarchical periodicities, not easily recognizable by other methods. The possible implications concerning the evolution of tandemly repetitive arrays are discussed in light of a model which involves, as successive steps, random repeat modification, the fusion of differently modified repeat versions into longer units, and the amplification of (and/or homogenization to) the more recent repeat units.

Algorithms↗
PubMed1990

Reorganization and merging of the EMBL and GenBank keyword indexes in a tree structure for more efficient retrieval of nucleic acid sequences.

EMBL and GenBank keyword indexes have no hierarchical structure. In this paper we present a method for merging and reorganizing them in a tree structure whose primary roots are the keywords 'protein', 'DNA', 'RNA', and 'unclassified'. Synonymous keywords have been grouped together and erroneous keywords have been corrected. This taxonomic organization of keywords results in a more extensive and efficient retrieval which is further aided by "synonyms declaration". The tree has been produced using the computer programs GENPOINT and CREANET.

Abstracting and Indexing↗
PubMed1988

A backtranslation method based on codon usage strategy.

This study describes a method for the backtranslation of an aminoacidic sequence, an extremely useful tool for various experimental approaches. It involves two computer programs CLUSTER and BACKTR written in Fortran 77 running on a VAX/VMS computer. CLUSTER generates a reliable codon usage table through a cluster analysis, based on a chi 2-like distance between the sequences. BACKTR produces backtranslated sequences according to different options when use is made of the codon usage table obtained in addition to selecting the least ambiguous potential oligonucleotide probes within an aminoacidic sequence. The method was tested by applying it to 158 yeast genes.

Amino Acid Sequence↗