Teamwork Between Shining Bacteria and Squids Evolved?


Certain strains of bacteria, named Vibrio, can establish a mutually beneficial link with a squid by a single gene switch, according to researchers at the University of Wisconsin.1 Could this precisely specified biochemistry really have evolved from the comparatively “simple” switching-on of just one gene, as their study suggests?

Vibrio bacteria have a well-orchestrated capacity to interact with specialized tissue found on the bobtail squid and the Japanese pinecone fish.2 A biochemical “conversation” takes place between animal and bacteria whereby the animal’s specialized tissue secretes a gummy substance that makes a good home for the bacteria. If the bacteria possess the correct genetic switch, it is turned “on” by the host’s specific chemistry, enabling the bacteria to secrete a special biofilm. Only in this environment do the bacteria begin to glow. The cold light emitted by the bacteria-infected light organ attracts prey for the animal, thus establishing a symbiotic relationship between the bacteria and their host.3

The researchers hypothesized that “by encoding a regulator and not an effector that interacts directly with the host, a single gene can contribute to the evolution of host specificity by switching 'on' pre-existing capabilities for interaction with animal tissue.”4 But where did the pre-existing capabilities come from? The genetic switch is a single necessary component of a long list of parts, some of which must interact “directly with the host,” and all of which must be present for the glow to show.

The newly-identified switch must properly link with molecules that specifically interact between the bacteria and the microbe, and these communicative chemicals are only useful in the context of fully-operable organisms. The facts are that the bacteria can manufacture biofilm and light, and the animal can build its pouch-shaped light organ, and these depend on many fully-formed parts.

The most plain, obvious, and scientific inference from these facts is that these systems came about by some plan. Further, the identity of this Planner as One who is both wise and capable is consistent with the omniscient biblical God.

References

  1. Devitt, T. Single gene lets bacteria jump from host to host. University of Wisconsin News. Posted on www.news.wisc.edu February 1, 2009, accessed February 3, 2009.
  2. The scientific names are Vibrio fischeri (bacteria), Euprymna scolopes (squid), and Monocentris japonica (pinecone fish).
  3. Sherwin, F. 2008. Squid Reflects Creation Evidence. Acts & Facts. 37 (4): 14.
  4. Mandel, M. J. et al. A single regulatory gene is sufficient to alter bacterial host range. Nature. Posted on nature.com on February 1, 2009, accessed February 3, 2009.

Image Credit: University of Wisconsin

* Mr. Thomas is Science Writer.

Article posted on February 10, 2009.