Fans of fictional characters such as Cyclops from the X-men, or Sookie Stackhouse from TrueBlood will appreciate the fantastic human ability to generate light, whether as concussive optic beams, or ambient mystical flashes. Nothing quite this spectacular exists in the real world, but humans may have evolved a subtle, but complex system of light detection and generation beyond what is normally expected.
Light detection is an expected characteristic in biology. Vision and photosynthesis are the most common manifestations of this ability, but there is now evidence that some of the molecular machinery related to sight can be found deep within the body, without an immediately apparent evolutionary rationale as to why it would be in tissues other than in the eyes. In a series of experiments on a species of eyeless fish, animals exposed to light consistently demonstrated avoidance behavior, termed negative phototaxis, despite the fact that they had no eyes. Maybe this ability to detect light within the body can be related to the notion that the body emits ultraweak photons, or biophotons that are below the threshold of normal visible detection. First proposed by Alexander Gurwitsch, light produced deep within the body was believed to be the result of chemi-excitation by reactive oxygen species produced by normal physiological reactions. In fact, it was believed that fluctuations in biophotons could be used as a diagnostic tool to characterize potential cancers in the body. Current research, using photomultipliers with increased sensitivity are exploring this possibility.
The notion of biologically generated light is not as radical an idea as it might first sound, as countless examples of the more recognized phenomenon of bioluminescence exist in nature. One of the most well recognized animals capable of generating light are members of Lampyridae, more commonly referred to as fireflies. In these insects, specialized light producing organs are the site of a chemical reaction involving an enzyme called luciferase. When this enzyme recognizes a specific target, called “luciferin”, the latter is chemically oxidized, releasing light in the process. This reaction is the archetype for other bioluminescent organisms, with the most intriguing facet being the innate patterns of light production that the organisms are capable of. In some species of fireflies, collective co-ordination of light production occurs in a precise manner called phase synchronization, a precise and spectacular phenomenon that causes an entire swarm to blink on and off as one entity, with rationales offered for differing and intricate light patterns suggesting specific courtship and hunting related behaviors.
So it seems that not only can we perceive the visible world around us, but we may quite literally be biological beacons who can use and process light in ways beyond the norm. Typically, the phrase “a beacon for others” evokes powerful images of a compassionate human being stretching out his or her hand to help others in need. How fascinating would it be then, to discover that we truly are beings of light, not just figuratively, but literally, as well.