Epigenetics

definition

heritable changes in gene function without changes to base sequence of dna

what is the DNA histone complex

dna and histones covered in chemical tags

what is the layer of tags on the DNA histone complex called and what does it do

epigenome

determines shape of DNA histone complex

what happens when DNA histone association is weak x4

complex is less condensed

(more) accessible to transcription factors

initiate transcription of mrna

gene is expressed

what is methylation

addition of a methyl group

where is a methyl group added

cytosine bases where C and G bases are next to each other (CpG sites) in DNA coding for a gene

effect of increased methylation and why

inhibits transcription

prevents binding of transcription factors to DNA

gene not expressed

what acetylation

addition of acetyl group to histones

effect of acetylation

DNA histone complex less condensed

effect of decreased acetylation and why

DNA histone complex condenses so prevents binding of transcription factors

prevents transcription

gene not expressed