Describe the impact of DNA methylation and histone acetylation on gene expression.
DNA methylation adds methyl groups to specific bases in DNA, which leads to turning off the transcription of some genes. This typically causes long-term inactivation of a gene. For example, the gene for humans to grow tails has been methylated, we only have a tailbone and cannot grow tails. Histone acetylation adds acetyl groups to the lysines in histone tails that are positively charged. [See “Wiggly Purple Guys” under Ch 16 & 17] This functions to loosen up the chromatin structure, so that transcription can be initiated. Also, methylation in chromatin can cause it to condense more. Phosphate groups added to methylated amino acids also can loosen up wound up chromatin.
DNA methylation adds methyl groups to specific bases in DNA, which leads to turning off the transcription of some genes. This typically causes long-term inactivation of a gene. For example, the gene for humans to grow tails has been methylated, we only have a tailbone and cannot grow tails. Histone acetylation adds acetyl groups to the lysines in histone tails that are positively charged. [See “Wiggly Purple Guys” under Ch 16 & 17] This functions to loosen up the chromatin structure, so that transcription can be initiated. Also, methylation in chromatin can cause it to condense more. Phosphate groups added to methylated amino acids also can loosen up wound up chromatin.
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