In normal adult tissues, the CpG sites at the repetitive regions of the genome are heavily methylated, while most of the CpG islands located at or near the promoter regions are unmethylated.
For example, during mammalian development, most CpGs remain methylated while CpG islands located in the promoters of housekeeping genes are hypomethylated [ 3].
Vertebrate genomes are globally methylated, with the most notable exceptions being CpG-rich stretches of DNA, termed CpG islands, located at the 5' ends of many genes (Bird, 2002).
Interestingly, recent findings show that most of the aberrant DNA methylation in cancer occurs in CpG island shores instead of CpG islands located in gene promoters [ 76], suggesting that CpG island shores can contribute to the tumorigenic process.
Group 2 and 3 also include the upper islands (those islands located in the northern area) and lower islands (those islands located in the southern area) in Shinan County.
The three models are tested with the data take from Dongshan hydrological station, Dongshan Town is a coastal island located at the most south of "golden delta" of Fujian Province, which lies between 117°17′E 117°35′E longitude and 23°33′N 23°47′N latitude, consisting Dongshan island and the rest 44 small islands, and covers an area of about 248.34 km2 (Fig. 1).
Rainsford Island is an 11-acre island located in central Boston Harbor, Massachusetts.
It is Pagang Island, located in West Sumatra.
Falker Island is a crescent-shaped island located three and a half miles offshore of Guilford, Connecticut.
We found that most probes hybridized within the area located from −600 to −450 bp from the TSS, which is a hot spot for methylation at the CpG island located in the IGFBP-3 promoter.
