mIFP is a monomeric infra-red fluorescent protein with an excitation peak of 683nm and an emission peak of 704nm in vitro. It is an artificial derivative of a bacteriophytochrome gene, 'BrBphP', from a Bradyrhizobium species. In order to fluoresce, mIFP requires a biliverdin cofactor to act as the chromophore. This can be supplied in a transgenic animal by including a transgenic construct that encodes a heme oxygenase (HO) (FBrf0229174).