CYC1 is a human gene that is conserved in chimpanzee, Rhesus monkey, dog, cow, mouse, rat, zebrafish, fruit fly, mosquito, C. elegans, S. cerevisiae, K. lactis, E. gossypii, S. pombe, N. crassa, A. thaliana, rice, and frog. There are orthologs of CYC1 in 137 known organisms.
In its structure and function, the cytochrome b-c1 complex bears extensive analogy to the cytochrome b6f complex of chloroplasts and cyanobacteria; cytochrome c1 plays an analogous role to cytochrome f, despite their different structures.