Biology / Unit 6 Bio 1323 short lesson, about 20 seconds
DNA Methylation
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The idea
DNA methylation adds a methyl group directly to certain DNA bases, typically silencing the gene's transcription without changing its sequence.
In practice
Heavily methylated DNA near a gene's promoter is generally associated with that gene being transcribed less or not at all.
Where people slip
Methylation, like histone modification, is an epigenetic change — it alters gene expression without altering the DNA sequence a mutation would change.
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