Detection of regions of genomic sequences that are rich in the CpG pattern is important because such regions are resistant to methylation and tend to be associated with genes which are frequently switched on. Regions rich in the CpG pattern are known as CpG islands. The function of the program cpgplot is to plot CpG rich areas, and cpgreport to report all CpG rich regions.
The nuclear genomes of vertebrates are mosaics of isochores, very long stretches of DNA that are homogeneous in base composition and are compositionally correlated with the coding sequences that they embed. Isochores can be partitioned in a small number of families that cover a range of GC levels. Program isochore plots GC content over a sequence.