Probably one of the most important things to understand about evolution is that

Probably one of the most important things to understand about evolution is that

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Probably one of the most important things to understand about evolution is that mutation is random , i.e., is not directed towards the problems presented by the environment (although some recent evidence has been published on bacteria that challenges this assumption: Lenski, R. E. Are some mutations directed? Trends in Ecology and Evolution vol. 4, pp. 148-150.). Mutation is an ongoing process. There are measurable mutation rates and that there can be a genetic variation for mutation rates; "mutator strains" of bacteria exist.
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Unformatted text preview: Mutations in the replication or repair machinery of DNA can alter mutation rates. Types of mutation: point mutation now generally refers to a change at a single nucleotide site. These can be transitions (purine to purine [A to G or G to A], or pyrimidine to pyrimidine [C to T or T to C]) or transversions (from a purine to a pyrimidine or vice versa). Synonymous and non-synonymous substitutions with respect to the effect on the amino acid coded for by the DNA. Deletions and insertion will cause frameshift mutations ....
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