 The majority of proteins, two-thirds in unicellular organisms and more than 80% in metazoa, are multidomain proteins.However, other studies concluded that 40% of prokaryotic proteins consist of multiple domains while eukaryotes have approximately 65% multi-domain proteins.Many domains in eukaryotic multidomain proteins can be found as independent proteins in prokaryotes, suggesting that domains in multidomain proteins have once existed as independent proteins.