LONG-RANGE CORRELATION AND PARTIAL 1/F-ALPHA SPECTRUM IN A NONCODING DNA-SEQUENCE

Mutual information function, which is an alternative to correlation function for symbolic sequences, and a <<symbolic spectrum>> are calculated for a human DNA sequence containing mostly intron segments, those that do not code for proteins. It is observed that the mutual information function of this sequence decays very slowly, and the correlation length is extremely long (at least 800 bases). The symbolic spectrum of the sequence at very low frequencies can be approximated by 1/f(alpha), where f is the frequency and alpha ranges from 0.5 to 0.85. It is suggested that the existence of the repetitive patterns in the sequence is mainly responsible for the observed long-range correlation. A possible connection between this long-range correlation and those in music notes is also briefly discussed.