DNA methylation generally reduces transcription.

• A. RNA processing does not affect transcription
• B. DNA methylation generally reduces transcription
• C. Histone acetylation enhances transcription
• D. Promoters accelerate transcription

Answer: (B)

DNA methylation is an epigenetic modification where methyl groups are added to cytosine bases, especially in CpG-rich regions near gene promoters. This addition tends to repress transcription because it can block the binding of transcription factors to promoter DNA and recruit proteins that promote a closed, compact chromatin state. With chromatin condensed, RNA polymerase II and the transcription machinery have reduced access to the gene, leading to lower transcription levels.

Understanding the contrast helps: histone acetylation loosens chromatin and usually enhances transcription by making DNA more accessible. Promoters are necessary for initiating transcription, but simply having a promoter doesn’t by itself speed up transcription beyond what transcription factors and chromatin state allow. RNA processing occurs after transcription and, while it can influence gene expression in some contexts, it does not determine transcription initiation in the same way DNA methylation does.