Correlations in DNA sequences across the three domains of life

We report statistical studies of correlation properties of similar to 7500 gene sequences, covering coding (exon) and non-coding (intron) sequences fo r DNA and primary amino acid sequences for proteins, across all three domai ns of life, namely Eukaryotes (cells with nuclei), Prokaryotes (bacteria) a nd Archaea (archaebacteria). Mutual information function, power spectrum an d Holder exponent analyses show exons with somewhat greater correlation con tent than the introns studied. These results are further confirmed with hyp othesis testing. While similar to 30% of the Eukaryote coding sequences sho w distinct correlations above noise threshold, this is true for only simila r to 10% of the Prokaryote and Archaea coding sequences, for protein sequen ces, we observe correlation lengths similar to that of "random" sequences. (C) 2000 Elsevier Science B.V. All rights reserved.