carlsonjok
Posts: 3326
Joined: May 2006
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That name sounded familiar.
From a report on the 2007 Wistar conference by Daniel R Brooks found here:
| Quote | The next presentation in this session was by Ann Gauger, a microbiologist and employee of the Biologic Institute, whose presentation was entitled, “Assessing the difficulty of pathway evolution: an experimental test.” Her presentation was remarkable in part because she performed experiments and reported original data.
She began with the repetitive attempt at a reductio ad absurdum, stating that the current complexity of metabolic pathways within cells could not have been created by gene duplication or gene recruitment (another name for co-option), and therefore they were designed. She suggested that contemporary evolutionists believe if there is not a payoff in terms of adaptive value within a few generations, any duplicated gene will be lost, and that for recruitment/co-option to work, function must change within a very few mutations. It is factually untrue that these assertions are an essential part of Darwinian theory. At most, they were initial starting points for investigations into protein evolution long ago, but today’s evolutionary biology does not adhere to any of them. Gene duplication is considered an integral part of evolutionary dynamics and one major source of the co-option that is so ubiquitous in evolution.
She suggested that when similar proteins are “arranged by hierarchy,” the evidence suggests they arose from a common ancestor that predates the eukaryote/prokaryote split and perhaps even the Archaea. Gauger thus, like Behe, accepted not only a phylogeny of life but an ancient singular origin of life. Then she embarked on a series of experiments designed to emulate 2 billion years of microbial evolution in Petri dishes over a few bacterial generations. Specifically, she wanted to see if either of two forms of a protein would mutate directly into the other under those experimental conditions. They did not.
Gunther Wagner congratulated Dr. Gauger on doing some great experimental work, but noted some logical inconsistencies in inference. The first is a phylogenetic comparative issue; it is necessary to know the ancestral state of the two proteins. If you are dealing with two proteins each derived separately from a common ancestor, then the experiment involves a minimum of two steps, backwards to the ancestral condition and then forwards to the alternative derived condition. It seems unlikely that you would be able to do that experimentally, especially if you have no idea of the environmental conditions under which the evolutionary diversification took place, and no idea if there were any intermediate forms that no longer survive. In response, Gauger admitted that the two proteins she studied are quite old and that studies of enzymes that are more recently diverged from each other report a lot of functional co-option, but only on a small scale.
She was then prompted by one of her colleagues to regale us with some new experimental finds. She gave what amounted to a second presentation, during which she discussed “leaky growth,” in microbial colonies at high densities, leading to horizontal transfer of genetic information, and announced that under such conditions she had actually found a novel variant that seemed to lead to enhanced colony growth. Gunther Wagner said, “So, a beneficial mutation happened right in your lab?” at which point the moderator halted questioning. We shuffled off for a coffee break with the admission hanging in the air that natural processes could not only produce new information, they could produce beneficial new information. |
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It's natural to be curious about our world, but the scientific method is just one theory about how to best understand it. We live in a democracy, which means we should treat every theory equally. - Steven Colbert, I Am America (and So Can You!)
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