## Abstract

Previous searches for long-range correlations in DNA sequences was carried out using statistical tools for stationary signals. However, genomic signals are non-stationary as can be attested by standard statistical tests for stationarity. In this paper, we address, in the light of non-stationary time-series analysis, the questions of (i) the existence of long-range correlations in DNA sequences and (ii) whether they are present in both coding and non-coding segments or only in the latter. It turns out that the statistical differences between coding and non-coding segments are more subtle than previously claimed by the stationary analysis. Both coding and non-coding sequences exhibit long-range correlations, as asserted by an evolutionary 1/f spectrum (i.e., having a time-dependent spectral exponent). Moreover, the average spectral exponent of non-coding segments is higher than its counterpart for coding segments. To prove that this observation is not an artifact of the 1/f evolutionary spectrum, we show, using an index of randomness that we derive from the frequency-time distribution of the genomic signals, that coding sequences are "more random" (i.e., whiter) than non-coding sequences. We believe that this result is likely the source of confusion and controversy in previous work, which relied on stationary analysis of DNA correlations.

Original language | English (US) |
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Title of host publication | 2007 IEEE/SP 14th Workshop on Statistical Signal Processing, SSP 2007, Proceedings |

Pages | 200-204 |

Number of pages | 5 |

DOIs | |

State | Published - Dec 1 2007 |

Externally published | Yes |

Event | 2007 IEEE/SP 14th WorkShoP on Statistical Signal Processing, SSP 2007 - Madison, WI, United States Duration: Aug 26 2007 → Aug 29 2007 |

### Other

Other | 2007 IEEE/SP 14th WorkShoP on Statistical Signal Processing, SSP 2007 |
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Country | United States |

City | Madison, WI |

Period | 8/26/07 → 8/29/07 |

## All Science Journal Classification (ASJC) codes

- Signal Processing