Mutation Rates

     Mutation rates do evolve. Mutations occur in genetic material, but the materials — the enzymes and proteins — that reproduce the genetic material can they themselves can be affected by mutation. When DNA polymerase or other proteins involved in DNA transcription are altered, the rate of mutation can change. It is more likely that DNA polymerase would be mutated to make more mistakes than be mutated to be more accurate and make less mistakes. It is common knowledge that the slower the DNA polymerase ‘reads’ and replicates, the more likely it will be to accurate place the correct complement amino acid base. The faster the DNA polymerase works, the more likely it is to make mistakes, and thus mutations, by placing an incorrect base pair. This incorrect nitrogenous base can then be used as the template strand in the future, and more ‘incorrect’ genetic material will be created in the future based off of this one error. There are enzymes and proteins utilized in transcription to catch and correct these mistakes, but the accuracy of proofreading relies on these mechanisms as well. These proofreading proteins can be mutated and further add to the changing mutation rate. The entire cell may decide to commit programmed cell suicide, called apoptosis, if the mutation is deleterious enough. The mechanisms that determine apoptosis may be mutated or damaged, and cancer may result. The mutation rate in this individual would certainly skyrocket as cancer is known to create more and more deleterious mutations as it progresses. Mutagens from the environment may also contribute to the mutations of replicating materials. 

    However, there are evolutionary advantages to changes in mutation rates. Mutation gives evolution a basis from which to apply natural selection. Mutation provides variation in a population. The more variation available, the more options that natural selection has to work with. Not all options may be beneficial for the individuals, so these will probably be selected against in that they will not be able to survive or reproduce as well and will not be able to pass on these mutations as well. This is more often the case because mutations are more often known to be deleterious. Mutations could be neutral as well. That is to say, the change in the base pair may not be significant enough that it changes the resulting protein. The mutation could be in a non-coding region of DNA as well, so its information would never be used to create a protein. However, some mutations can be beneficial for the individual and overall population, so natural selection will select for this trait by making the organism better able to adapt, survive, and reproduce in their environment. They will then be able to spread this mutation further in the generations that they create.