It suggests that type 1 rhodopsins gave the birth to all GPCRs and type 2 rhodopins managed to retrieve the lost function of photoreception.

• 这暗示1型视紫红质是所有的G蛋白偶联的受体的祖先，并且2型视紫红质在进化过程中捡回了曾经丢失的感光能力。