High statistics block entropy measures of DNA sequences

P Lio, A Politi, M Buiatti, S Ruffo

Research output: Contribution to journalArticle

26 Citations (Scopus)

Abstract

We have used an improved block-entropy measure in order to gain some further insights into the short-range correlations present in whole chromosomes of S. cerevisiae, viruses and organelles and very large genomic regions of E. coli. Although DNA sequences are largely inhomogeneous and word frequencies are unevenly distributed, the comparison of entire chromosomes and large genomic regions show a ''bulk'' composition homogeneity. This property suggests that biases in selection, directional mutational pressure and recombination processes act in homogenizing the base composition of the DNA molecules within a genome but their mode of action, relative impact and direction may vary in different organisms. The most interesting results appear to be the differences between the SW (C,G/A,T) and RY (A,G/C,T) two-letter alphabet entropies. Deviations from randomness in E. coil and S. cerevisiae sequences particularly concern SW dinucleotide frequencies and RY tetranucleotide frequencies. (C) 1996 Academic Press Limited

Original languageEnglish
Pages (from-to)151-160
Number of pages10
JournalJournal of Theoretical Biology
Volume180
Issue number2
Publication statusPublished - 21 May 1996

Keywords

  • NUCLEOTIDE-SEQUENCES
  • CODON USAGE
  • GENOME
  • MUTATION
  • RECOMBINATION
  • CONSTRAINTS
  • STABILITY
  • EVOLUTION
  • RNA

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