生物問題請問 - 考試

The addition of methyl groups (-CH3) to
histone tails (methylation) can promote condensation of the
chromatin. The addition of a phosphate group to an amino
acid (phosphorylation) next to a methylated amino acid can
have the opposite effect.
這是課本的一段話
我看不太懂
想請好心人幫忙解釋
謝謝

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