title: The fuzzy polynucleotide space: basic properties.
abstract: BACKGROUND
  Any triplet codon may be regarded as a 12-dimensional fuzzy code. Sufficient information about a particular sequence may not be available in certain situations. The investigator will be confronted with imprecise sequences, yet want to make comparisons of sequences. Fuzzy polynucleotides can be compared by using geometrical interpretation of fuzzy sets as points in a hypercube.
  
  
  RESULTS
  We introduce the space of fuzzy polynucleotides and a means of measuring dissimilitudes between them. We establish mathematical principles to measure dissimilarities between fuzzy polynucleotides and present several examples in this metric space. We calculate the frequencies of the nucleotides at the three base sites of a codon in the coding sequences of Escherichia coli K-12 and Mycobacterium tuberculosis H37Rv, and consider them as points in that fuzzy space. We compute the distance between the genomes of E.coli and M.tuberculosis.
authors.affiliation: Departamento de Psiquiatría, Radiología y Salud Pública, Facultad de Medicina, Universidad de Santiago de Compostela, Spain.
authors.forename: Angela
authors.initials: A
authors.lastname: Torres
authors.forename: Juan J
authors.initials: JJ
authors.lastname: Nieto
mesh_terms: D000465:Algorithms; D003062:Codon / Q000235:genetics; D004269:DNA, Bacterial / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics*; D017143:Fuzzy Logic; D005787:Gene Frequency / Q000235:genetics*; D016680:Genome, Bacterial; D009169:Mycobacterium tuberculosis / Q000235:genetics*; D011119:Polynucleotides / Q000235:genetics; D016415:Sequence Alignment / Q000379:methods*; D017422:Sequence Analysis, DNA / Q000379:methods*
chemical_list: D003062:Codon; D004269:DNA, Bacterial; D011119:Polynucleotides