First Lab Demonstration That the Ability To Evolve Can Itself Evolve

ananyo writes "Research on Borrelia burgdorferi, the bacterium that causes Lyme disease, shows that the capacity to evolve can itself be the target of natural selection. B. burgdorferi can cause a chronic infection even if its animal host mounts a strong immune response — evading those defenses by tweaking the shape and expression of its main surface antigen, VIsE. A series of unexpressed genetic sequences organized into 'cassettes' recombine with the VIsE gene, changing the resulting protein such that it escapes detection by the host's immune system. The researchers studied the molecular evolution of the cassettes' genetic sequences in 12 strains of B. burgdorferi. They found that natural selection seemed to favor bacteria with more genetic variability within their cassettes, and hence a greater capacity to generate different versions of the antigen. 'Greater diversity among the cassettes in itself shouldn't be a selective advantage considering they aren't expressed and don't do anything else,' says lead author Dustin Brisson. 'But we did find evidence of selection, so the question is: what else could it be for besides evolvability?'"

Comments

Common sense

[JustNiz]

It just seems common sense to me that if evolution can/does affect every mechanism in a living organism, then the mechanism governing the ability to evolve must itself be included.

Re:Common sense

[abroadwin]

You're right, it is common sense. My initial reaction to this was the same as yours. That said, it's very useful to verify common sense scientifically, because it's amazing how often common sense proves to be wrong when formally tested. Take nothing on faith, not even (and perhaps especially) the obvious.

Why is this suprising?

[JoeyRox]

Maybe I'm overlooking the significance of this discovery but why is it surprising that a bacteria strain with a greater "genetic variability" would fall under natural selection? Wouldn't such a strain naturally survive others considering it allows the bacteria to rearrange antigens and thus the ability to evade detection and destruction by the host's immune system, even if those latent facilities aren't immediately apparent to an observer who doesn't know the full evolutionary history of the strain?

exactly_research 'begs the question'

[globaljustin]

if evolution can/does affect every mechanism in a living organism, then the mechanism governing the ability to evolve must itself be included.

yes.

these researchers created a *false distinction* in their research question

They took what you call 'the mechanism governing the ability to evolve' and found a behavior in nature that they could drive a false dichotomy wedge into to create a *factor* where none exists. Here is where they invent the distinction out of *thin air* based on their personal opinion:

'Greater diversity among the cassettes in itself shouldn't be a selective advantage considering they aren't expressed and don't do anything else,' says lead author Dustin Brisson.

highlighted portion is **pure speculation** and forms the leverage for their whole experiment...if that ***opinion*** by the research is wrong the whole thing sinks...and it is just that one dude's opinion...which is not how a scientific research question is formed

bottom line: the process they describe, the bacteria being selected b/c some are more likely to survive is absolutely 100% main line accepted theory...their work does not in any way represent a new or different behavior in life

disclaimer: I am not a creation science supporter...i hate it...but I also hate equally the notion that **science can prove God does or does not exist**...looking at bacteria to somehow 'prove' evolution makes 'god' a delusion is itself a delusion.

science cannot prove **OR** disprove something abstract like a supernatural 'god'