Statistical Analysis of the DNA Sequence of Human Chromosome 22

Dirk Holste1, Ivo Grosse2, and Hanspeter Herzel3

1.Department of Theoretical Biophysics, Humboldt University Berlin, Invalidenstrasse 42, D-10115, Berlin, Germany
2.Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724
3. Institute for Theoretical Biology, Humboldt University Berlin, Invalidenstrasse 43, D-10115, Berlin, Germany
Physical Review E, 64(4), article 041917 (2001)

Abstract

We study statistical patterns in the DNA sequence of human chromosome 22, the first completely sequenced human chromosome. We find that (i) the 33.4 x 106 nucleotide long human chromosome exhibits long-range power-law correlations over more than four orders of magnitude, (ii) the entropies Hn of the frequency distribution of oligonucleotides of length n (n-mers) grow sublinearly with increasing n, indicating the presence of higher-order correlations for all of the studied lengths 1 <= n <= 10, and (iii) the generalized entropies Hn(q) of n-mers decrease monotonically with increasing q and the decay of Hn(q) with q becomes steeper with increasing n <= 10, indicating that the frequency distribution of oligonucleotides becomes increasingly nonuniform as the length n increases. We investigate to what degree known biological features may explain the observed statistical patterns. We find that (iv) the presence of interspersed repeats may cause the sublinear increase of Hn with n, and that (v) the presence of monomeric tandem repeats as well as the suppression of CG dinucleotides may cause the observed decay of Hn(q) with q.