I am currently contemplating bioluminescence in Vibrio cholerae, the cholera bacteria. Initially, the presence of LuxA, a gene for luminescence, seems to be a classic argument for a vestigial marker for evolutionary descent. Further reading led me to this note:
“It has been proposed that expression of the luciferase gene may help facilitate the bacterial DNA repair process by providing an internal light source for photoreactivation, a photo-mediated repair mechanism (4, 12). Alternatively, when attached to larger particles, such as detritus or plankton, V. cholerae may be afforded protection from UV damage, as would occur in Bangladesh ponds where turbidity is high (1). Further investigation of the functionality of the lux operon for the apparently nonsymbiotic but commensal species V. cholerae is needed, since the phenotype occurs more frequently than previously determined and demonstrates a dynamic expression range” (Grim, et al., 2007).
The speculative statements at the end of the Grim (2007) article suggests that bioluminescence is purposeful, rather than incidental, as it may be used for “photo-mediated repair” or may provide communal benefits in murky waters. “Dynamic expression range” is an attribute that occurs in many species including those far removed from cholera bacteria. For example, trichromacy (color vision) reveals dynamic expressive range because it occurs in some New World monkeys (like Howler monkeys) but not others. Bioluminescence, trichromacy, and other aptitudes are sometimes explained as having been “independently acquired” because they do not neatly fit cladistic analyses. It is more parsimonious to recognize the possibility that these are the result of divinely-designed dynamic genetic cadres. Dynamic Expressive Range is the sin qua non of divine design. The Master’s Hand can most clearly be seen in polyarchic systems which may seem brutally utilitarian at first glance, but result in a complex, but enduring natural order.
Some intelligent design (ID) theorists focus on individual species for evidence of divine design. My observation has been that for every example of elegance, an inelegant or dubious example can often be provided as well (this fact gave Stephen Jay Gould much to write about.) It is more productive to focus upon divinely appointed processes including adversarial, symbiotic, complementary, and communal algorithms which occur within the genome and between species. Just as heliocentric astronomers were befuddled by the elliptical trajectories of planetary orbits, so theistic metaphysical theorists will continue to be frustrated if they focus on individual species rather than the regi (guiding principles) in the Natural Order. They have focused too much energy looking for evidence of deus ex machina and too little on regi ex machina.
Grim, Taviani, Alam, Huq, Sack, & Colwell (2007). “Occurrence and Expression of Luminescence in Vibrio cholerae.” Appl Environ Microbiol. 2008 February; 74(3): 708–715. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2227713/
Kainz, Neitz, & Neitz (1998). Recent evolution of uniform trichromacy in a New World monkey. Vision Research 38 (1998) 3315–3320.