Abstract
It was generally believed that autosomal CpG islands (CGIs) escape methylation. However, our comprehensive analysis of allelic methylation status of 149 CGIs on human chromosome 21q revealed that a sizable fraction of them are methylated on both alleles even in normal blood cells. Here, we performed a similar analysis of 656 CGIs on chromosome 11q, which is gene-rich in contrast with 21q. The results indicate that 11q contains less methylated CGIs, especially those with tandem repeats and those in the coding or 3′-untranslated regions (UTRs), than 21q. Thus, methylation status of CGIs may substantially differ from one chromosome to another.
Acknowledgements
This work was in part supported by research grants from Ministry of Education, Culture, Sports, Science and Technology, Japan.
Notes
† These two authors equally contributed to this work.