Study identifies mechanisms cells use to remove bits of RNA from DNA strands

http://www.biologynews.net/archives/2011/12/04/study_identifies_mechanisms_cells_use_to_remove_bits_of_rna_from_dna_strands.html

when small  RNA component units called ribonucleotides become a part
of DNA, they can instability for the cell which can cause anomalies in cellular
metabolism. A new study has been published that has shown how these
ribonucleotides are actually removed from DNA. Most of the work is done with
two enzymes called ribonucleases H and the DNA mismatch repair the system.
The key thing is that this is usually the mechanism that goes wrong when people get
weird genetic modifications. in fact, cancer is often a result of this mismatch.