| Basis of differentiation | GFP | YFP | 
| Definition | GFP is a wild-type green fluorescent protein that is used in molecular cloning of non-mammalian cells | YFP (Yellow fluorescent protein) is a genetic mutant of GFP | 
| Color of emitted light | Emits green color light | Emits yellow color light | 
| Excitation peak | Major peak is at 395nm, while the minor peak is at 475 nm | Excitation peak is at 514 nm | 
| Emission peak | Emission peak is at 509 nm | Emission peak is at 527 nm | 
| Significance | Is used as a reporter of expression and to visualize the localization of fused proteins | Used as non-invasive intracellular pH biosensors or fluorescence indicators for Ca2+ concentrations |