Large scale features in DNA genomic signals

Complex representations of the nucleotides, codons and amino acids derived from the projection of the Genetic Code Tetrahedron on adequately, oriented planes are presented. By converting the sequences of nucleotides and polypeptides into digital genomic signals, this approach offers the possibility of using signal processing methods for the analysis of genomic information. New tools for genomic signal analysis are introduced at the nucleotide, codon and amino acid levels, in a multiresolution approach. It is shown that some important features of nucleotide sequences can be revealed using these signal representations. The paper reports the existence of large scale and global trends of DNA genomic signals in both eukaryotes and prokaryotes, reflecting an almost constant second order nucleotide statistics along DNA strands even at the points where the first order nucleotide statistics show marked changes, as it is the case in prokaryotes. (C) 2002 Elsevier Science B.V. All rights reserved.