The distribution of CpG islands in mammalian chromosomes

• Published in: Nature genetics Vol. 7; no. 3; pp. 376 - 382
• Main Authors: Craig, Jeffrey M, Bickmore, Wendy A
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group 01.07.1994
• Subjects: Animals; Base Sequence; Biological and medical sciences; Cells, Cultured; Chromosome Banding; Chromosome Mapping; Chromosomes, Human - ultrastructure; Cytogenetics; DNA Replication; DNA Restriction Enzymes; Electrophoresis, Gel, Pulsed-Field; Female; Fundamental and applied biological sciences. Psychology; Genes; Genetic Markers; Genetics of eukaryotes. Biological and molecular evolution; Genome, Human; Human; Humans; In Situ Hybridization, Fluorescence; Lymphocytes - ultrastructure; Male; Mammals - genetics; Methylation; Molecular Sequence Data; Polymorphism, Genetic; Repetitive Sequences, Nucleic Acid; Genetic mapping; Human; Genome organization; Chromosome R banding; GC rich sequence; Chromosome T banding; Cytogenetics; Chromosome; Replication; Localization
• ISSN: 1061-4036; 1546-1718
• DOI: 10.1038/ng0794-376

Using fluorescent in situ suppression hybridization to metaphase chromosomes, we have directly shown that CpG islands are predominantly found in the early replicating (R band) regions of the genome. Conversely, late replicating (G band) DNA is sparsely populated with islands. The very highest concentration of CpG islands is in a subset of R bands, most of which are known as T bands. We suggest that there is an interdependence between the differences in island density and the behaviour of chromosomal domains. Our findings indicate which regions of the genome will yield the highest density of coding sequence information. An awareness of local island density may influence the choice of method for identifying exons in genomic DNA.