Evolutionary origin and methylation status of human intronic CpG islands that are not present in mouse.

ABSTRACT: Imprinting of the human RB1 gene is due to the presence of a differentially methylated CpG island (CGI) in intron 2, which is part of a retrocopy derived from the PPP1R26 gene on chromosome 9. The murine Rb1 gene does not have this retrocopy and is not imprinted. We have investigated whether the RB1/Rb1 locus is unique with respect to these differences. For this, we have compared the CGIs from human and mouse by in silico analyses. We have found that the human genome does not only contain more CGIs than the mouse, but the proportion of intronic CGIs is also higher (7.7% vs. 3.5%). At least 2,033 human intronic CGIs are not present in the mouse. Among these CGIs, 104 show sequence similarities elsewhere in the human genome, which suggests that they arose from retrotransposition. We could na

SUBMITTER: Rademacher K 

PROVIDER: S-EPMC4122923 | biostudies-literature | 2014 Jun

REPOSITORIES: biostudies-literature