
A schematic of the evolution of the complement system. (Solid line) The pathway has experimental evidence; (dashed lines) no experimental support; (?) the existence of the item or pathway is not verified; (*) amphiMASP1/3 gene can produce two proteins, MASP1 and MASP3; (**) amphioxus contains the most abundant CCP domains, see Supplemental Table S1; (***) the human C1q proteins recognize antibody, while the lamprey C1q serves as a lectin.











