Evidence that cytoskeletal elements have ancient origins comes from

-the sequence similarities of cytoskeletal elements when comparing distantly-related organisms.

-the presence of cytoskeletal elements in both eukaryotes and prokaryotes.

-the observation that both prokaryotes and eukaryotes use cytoskeletal elements to assist cell division.

-the ability to form functional hybrid microfilaments from actin monomers taken from distantly-related organisms.