What's the difference between intwine and untwine?

Intwine

Definition:

• (v. t.) To twine or twist into, or together; to wreathe; as, a wreath of flowers intwined.
• (v. i.) To be or to become intwined.

Example Sentences:

Untwine

Definition:

• (v. t.) To untwist; to separate, as that which is twined or twisted; to disentangle; to untie.
• (v. i.) To become untwined.

Example Sentences:

• (1) Chromosomes partly untwine but remain attached at their kinetochores.