Name 2 forms of epigenetic modification, and explain the effect they have on the genotype.

Acetylation: addition of an acetyl group to a histone molecule. Forces DNA strands apart, allowing easier access for RNA polymerase for transcription. Therefore increases expression of target gene(s) due to increased rate of transcription.Methylation: addition of a methyl group to the sugar-phosphate backbone of DNA. Makes it more difficult for RNA polymerase to bind to the DNA. Therefore decreases expression of target gene(s) due to decreased rate of transcription.