The Drosophila gene Enhancer of zeste is responsible for carrying out one of these reactions using a conserved SET domain. Tudor and PHD domains have been shown to recognize the results of these reactions. The endonuclease MutH does not nick molecules with this modification. Paul Modrich found DNA mismatch repair recognizes defective strands by their (*) lack of this modif
The Drosophila gene Enhancer of zeste is responsible for carrying out one of these reactions using a conserved SET domain. Tudor and PHD domains have been shown to recognize the results of these reactions. The endonuclease MutH does not nick molecules with this modification. Paul Modrich found DNA mismatch repair recognizes defective strands by their (*) lack of this modification. The anti-cancer drug Azacitidine removes these modifications which are propagated during replication by DNMT1. CpG islands are targets for this modification. Unlike histone acetylation, which always activates transcription, this modification can be activating or inactivating. For 10 points, name this chemical modification involving the addition of a CH3 group. 
The Drosophila gene Enhancer of zeste is responsible for carrying out one of these reactions using a conserved SET domain.
methylation [accept adding methyl groups, or specifics like DNA methylation] 