Friday, July 11, 2008

Answers in Genesis on E.Coli and Citrate Evolution

Well, I knew it would happen sooner or later: Answers in Genesis has jumped on the defensive at the report of E. Coli evolving the ability to utilize Citrate. Dr. Georgia Purdom writes:

"While the fitness of the bacteria has increased (as compared to the starting bacteria), it has come at a cost. For example, all the lines have lost the ability to catabolize ribose (a sugar). Some lines have lost the ability to repair DNA. These bacteria may indeed be more fit in a lab setting, but if put in competition with their wild-type (normal) counterparts in a natural setting, they would not stand a chance."

This is a very common creationist tactic: Try to make evolution seem like a detrimental process, and then claim that as evidence that common descent is false. The fact is that it is totally unreasonable to expect mutations to prove useful in every single environment possible. The role of mutation and natural selection is to make the organism better adapted to the environment the species is in at the time. For instance, gills are extremely useful if you live in the water (of course), but if a population of amphibians has evolved to the point of no longer truly needing them, it is best to get rid of them (why keep something that requires caloric energy to upkeep?). Legs are a great adaption if you need to move around on land, but for a sea dwelling creature like a whale they are nothing but a burden. Moving on:

"Many evolutionists state that the bacteria are experiencing 'adaptive evolution.' However, this is not evolution but rather adaptation. Molecules-to-man evolution requires an increase in information and functional systems. Instead, these bacteria are likely experiencing a loss of information and functional systems as has been observed in other mutant bacteria in Lenski’s lab. While these changes are beneficial in the lab environment, it does not lead to a net gain that move bacteria in an upward evolutionary direction."

Another creationist tactic: Try and redefine evolution for their own purposes. If you have read Carl Sagan's Baloney Detection Kit, you may recall Carl Sagan stating, "An important art of politicians is to find new names for institutions which under old names have become odious to the public." If you are fighting evolutionary theory, it might be helpful if you redefine the parts of it which you accept as something else. The fact is that evolution is nothing more than population adaption: Evolution is a change in the gene pool over time. After that, Dr. Purdom jumps into the old creationist argument that "evolution cannot prduce new information". Do they think that repeating this assertion again and again will make it true? Here is a peer reviewed paper that discusses the origin of a novel RNA gene (basically a gene cobbled together from a couple of older genes, but useful to the organism nevertheless). I have written an extensive answer to the creationist information argument, you may view it here. Finally, we see a horrible mischaracterization: Bacteria should "move upward in an evolutionary direction". What? There is no "moving up" in evolution; Evolution is only a series of adaptations. To continue:

"Since E. coli already possess the ability to transport and utilize citrate under certain conditions, it is conceivable that they could adapt and gain the ability to utilize citrate under broader conditions. This does not require the addition of new genetic information or functional systems (there are no known 'additive' mechanisms)."

While it is true that E. Coli can utilize Citrate under anoxic conditions (as well as in the presence of an oxidizable cosubstrate), E. Coli have only been able to utilize citrate if they mutated, such as Lenski's research suggests (BG Hall also reported some E. Coli which could utilize citrate, but even they had a chromosomal mutation). The bit about "added genetic information" is, as previously discussed, pure nonsense. Dr. Purdom, the author of this article, has a PhD in Molecular Genetics, and I would expect her to know about insertion mutations and genetic duplications. I'm sure she does, but why exactly do these not count as 'new information'?

In closing, I am porviding links to Olivia Judson's NY Times Series on the origin of new genes:

Gene Trafficking - Discusses horizontal gene transfer. Interesting statement: "The fungi that live in cows’ stomachs appear to have received their genes for digesting cellulose (cellulose again!) from bacterial co-occupants of the stomach."

Some Genes Come in Packages - Talks about Endosymbiosis and how the genomes of other organisms can be incorporated into genomes.

It's a Jumble Out There! - "Jumping Genes" and Evolution.

Evolution in Duplicate - How genes, chromosomes, and pieces of genes and chromosomes duplicate and their effects on evolution.


Brian said...

Once again a bunch of slack-jawed idiots criticizing evolution when they have no idea what it is in the first place.

Brian said...

These new e.coli couldn't stand a chance in the wild because the environment in the wild hasn't changed. The environment is what dictates what survives. I honestly fail to see their point here. Because it's in a lab the experiment is invalid? Because an evolutionary adaptation has drawbacks, that means it didn't happen?

nosatalian said...

You seem to be very worked up about arguing and refuting creationists. Give up. These people are brainwashed. There are very few religious people who are open to reasonable scientific debate. If they were- they would have lost their 'faith' long ago.