Proposal
Mutations alter the nucleotide sequence of the DNA. They may affect the organism’s phenotype, which can play a key role in bacterial adaptation and transformation to changing environments. Some of these mutations even appear to be beneficial to the organism. However, creationists have tended to offer an inconsistent or incomplete perspective of “beneficial mutations” within a creation framework. This includes the frequent denial that mutations can ever provide a beneficial phenotype, and the concept that “beneficial mutations” are merely an evolutionist exaggeration.
In bacteria, a wide range of mutations can be shown to provide a beneficial phenotype to the cell. These benefits are often of sufficient phenotypic affect that they can undergo strong positive selection. But, the benefits are generally temporary and limited. Some common examples of beneficial mutations are those involved in bacterial antibiotic resistance. These mutations potentially enable the bacterium to survive exposure to various antibiotics, but the resistance results from loss or reduction of pre-existing activities such as enzymatic, regulatory, or transport systems. Bacteria also can undergo adaptive mutation; a phenomenon used by bacteria to survive very specific stressful conditions. The exact mechanism is controversial because some results suggest a directed mutation specifically enabling adaptation to the environment, but at a mutation rate higher than random mutations would produce. Various mutations have also been found that enable bacteria to survive temporary exposure to high temperatures or starvation. Such mutations usually involve loss of certain sigma factors, reduction of DNA repair, or loss of specific regulatory controls. Other examples include several subpopulations of mutant strains of bacteria obtained over a period of up to 20,000 generations. These mutants have a greater “fitness” than the wild-type strain. However, analysis showed that most contained deletion mutations in various genes.
Each of these examples, as well as numerous others, involves certain environmental conditions that make these mutations phenotypically beneficial. However, these mutations frequently eliminate or reduce pre-existing cellular systems and functions. This has been referred to as antagonistic pleiotropy; meaning the cell experiences a trade-off where a temporary benefit for surviving one environmental condition is provided at the expense of systems used for other environments. If the environmental conditions change, the mutation usually becomes less beneficial and perhaps even detrimental. Hence, these mutations do not provide a genetic mechanism that accounts for the origin of biological systems or functions. Rather, they require the prior existence of the targeted cellular systems. As such, beneficial mutations of bacteria fit concisely within a creation model where (a) biological systems and functions were fully formed at creation, (b) subsequent mutations can provide conditional benefits that enable the organism to survive harsh post-Fall conditions even though the mutation is generally degenerative, and (c) most bacteria need the ability to rapidly adapt to ever changing environments and food sources.
Keywords
Mutation, Hypermutable, Evolution, Adaptive mutation, Natural selection
Print Reference
Pages 73-86
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Recommended Citation
Anderson, Kevin L. and Purdom, Georgia
(2008)
"A Creationist Perspective of Beneficial Mutations in Bacteria,"
Proceedings of the International Conference on Creationism: Vol. 6, Article 9.
Available at:
https://digitalcommons.cedarville.edu/icc_proceedings/vol6/iss1/9