CpG island Searcher.
CpG islands are generally described as 200-bp stretch of DNA with a C+G content of 50% and an observed CpG/expected CpG in excess of 0.6. CpG islands located in the promoter regions of genes can play important roles in gene silencing and imprinting.
With CpG island Searcher you can select the following criteria to screen your DNA sequences:
Gap between adjacent islands
The algorithm and criteria are described by Takai and Jones in Comprehensive analysis of CpG islands in human chromosomes 21 and 22. PNAS. 2002 Mar 19;99(6):3740-5.