I have a vague recollection of performing experiments along these lines in a molecular biology class many, many years ago. The purpose of the experiments was to confirm that the bacteria's acquired ability to metabolize lactose was due to random mutations and not due to its 'remembering' a preexisting function that had been disabled. In these experiments, lactose incompetent E. coli were grown on a glucose medium, where they thrived and the glucose was slowly replaced with lactose. This killed almost all the bacteria, but if the switch to lactose was slow enough, a few colonies of lactose competent bacteria would emerge and spread over the lactose infused petri dish.
That the change in the bacteria to lactose competence was due to random mutations was established in two ways. First, several samples were run with varying rates of conversion from glucose to lactose. If the switch was too fast, all the bacteria died and no lactose competence emerged. If the switch over was slower, the few colonies with lactose competence emerged as described above. If the emergence was due to re-learning an existing capability and only a few bacteria survived the switch over, that just meant that some bacteria were faster learners than others. Using a very gradual switch over would allow all the bacteria time to 'learn' the new competency and (almost) all would survive. But even with extremely slow switch over, almost all the bacteria died and only a few competent strains emerged. A detail statistical analysis (which was one of the main points of the exercise) showed that the 're-learning' conjecture was not supported and a random process was involved.
The second set of experiments was even more direct proof (particularly for those uneasy with the statistical analysis.) Another set of glucose to lactose switch over experiments were performed, but this time, some of the samples were exposed to various levels of mutagenic agents: ultra-violet light, gamma-rays from a cobalt 60 source, and the chemical mutagen Na3N (sodium azide, the same stuff used to inflate automobile air bags!) The mutagens increased the rate at which the lactose competent colonies emerged in precisely the way predicted for a random mutation process.
As I said, this is a vague memory from long ago - I'm not even sure we performed these experiments as described or just read about them - so if anyone can correct me if I erred in my description or has any more concrete references , I would be interested in seeing them. It would also be interesting to know if anybody has sequenced the genomes of the bacteria before and after the lactose competence was acquired to show that it was not due to a disabled capability and to show the details of the genetic changes. In the meantime it is amusing to see the evolution deniers plunge into the 'information' issue and then try to rationalize that the loss or gain of critical competences does connote not connote a change of information or that the order of symbols in a sequence is not germain to that sequences information content. The logical extension of this is that there is no significant difference between being alive and being dead since there is no information loss involved.
On the other hand, I have to admit that the lactose competent colonies were still of "bacteria kind".
Edited by AnswersInGenitals, : because the voices told me to.
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