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ScienceNOW: “What Doesn't Kill Microbes, Makes Them Stronger” New research into how microbial resistance to antibiotics comes about sheds light on the process that is frequently called “evolution.” Will creationists have to change their tune?
No new genetic information has appeared, making the process quite different from the usual portrayal of “evolution.”
Research led by Harvard University biologist James Collins investigated a process whereby antibiotics trigger the release of “reactive oxygen species” (ROS, a.k.a. free radicals) inside infectious microbes, causing mutations in their DNA that can lead to antibiotic resistance. This process is thought to be separate from the usual view of antibiotic resistance, whereby microbes that are already resistant to antibiotics survive while others die, giving the appearance that the population has evolved a new trait. Creationists point out that no new genetic information has appeared, making the process quite different from the usual portrayal of “evolution.”
Hypermutability, as it’s called, occurs when microbes are exposed to antibiotics that trigger the production of free radicals. In sufficient concentrations, the resulting mutations are so severe that the entire microbe population is killed—i.e., the antibiotic is successful. But what about dangerous but less-than-lethal doses of antibiotics? Could this hypermutability result in mutations that render the microbes resistant without killing them?
Collins’ team tested the hypothesis by treating E. coil with low levels of common antibiotics. The researchers observed up to eight times the number of mutations in the bacteria, with the resulting populations resistant to not only the antibiotics they were exposed to, but others as well.
ScienceNOW spoke with Baylor University molecular geneticist Susan Rosenberg, who noted that “antibiotics aren’t just selecting certain mutations, but causing them” (in the report’s words). However, the news does not contradict creationists’ point that no new genetic information is present in resistant microbe populations. Even if the mutations causing resistance are occurring after the exposure to antibiotics, previous research suggests the mutations are nonetheless information-destroying. This is evidenced by the fact that resistant populations are generally less biologically fit than non-resistant populations, indicating that the microbes pay a heavy genetic price for becoming resistant.
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