Spectral analysis of guanine and cytosine fluctuations of mouse genomic DNA

摘要

We study global fluctuations of the guanine and cytosine base content (GC) in mouse genornic DNA using spectral analyses. Power spectra S(f) of GC fluctuations in all nineteen autosomal and two sex chromosomes are observed to have the universal functional form S(f) similar to 1/f(alpha) (alpha approximate to 1) over several orders of magnitude in the frequency range 10(-7) 10(-5) cycle/base) shows a flattened power-law function with a < 1 across all twenty-one chromosomes. The substitution of about 38 interspersed repeats does not affect the functional form of S(f), indicating that these are not predominantly responsible for the long-ranged multi-scale GC fluctuations in mammalian genomes. Several biological implications of the large-scale GC fluctuation are discussed, including neutral evolutionary history by DNA duplication, chromosomal bands, spatial distribution of transcription units (genes), replication timing, and recombination hot spots.