Later, by the sequence similarity, a similar protein was found in Chlamydomonas algae,[10] showing that this regulatory subsystem existed a long time before the angiosperms lost the independent conversion enzyme. In a different manner, the Chlamydomonas regulatory protein is more complex: It is larger, crosses the thylakoid membrane twice rather than once, contains more protein-protein interactions sites, and even undergoes alternative splicing. It appears that the regulatory system underwent simplification during evolution.