List some ways that histones can be covalently modified.

Histones are the proteins that associate with DNA and help condense it into chromatin. Histone can be covalently modified in the following ways: methylation, phosphorylation, acetylation, ubiquitylation, and sumoylation.

Acetylation: The addition of the acetyl group to the histone tail is acetylation. It occurs in and histones. This weakens the positive charge of DNA. It has a role in cell cycle regulation, cell proliferation, and apoptosis.

Methylation: In this process, a methyl group is added to the lysine and arginine of the Histone tail.

Phosphorylation: In this, the phosphate group is added to the histone molecule. It has a role in DNA damage and repair mechanisms.

Ubiquitylation: In this modification, ubiquitin monomers are added to the lysine residue of the histone molecule. It alters the chromatin structure.

Sumoylation: It is the attachment of the Small Ubiquitin-like Modifier (SUMO), which are the small proteins that alter the functions of other proteins