BIOL 1101 Chapter Notes - Chapter 14: Germline Mutation, Synonymous Substitution, Transposable Element
Document Summary
Mutations result from mistakes in dna replication or from unprepared damage to dna. Most mutations are spontaneous (occur by chance in the absence of any assignable cause); occur randomly (unconnected to organism"s need) Rna viruses and retroviruses have high rate of mutation because rna is a less stable molecule than rna. Replication of these gnomes also lacks a proofreading function. Across the genome as a whole, mutation is common. Seeming paradox arises because humans have a large genome and undergo many cell divisions per generation: humans: average number of newly arising nucleotide-substitution mutations per genome in one generation is about 30 (60 per diploid zygote) Only 2. 5% of the genome codes for proteins. Most of the newly arising mutation occur in noncoding dna, so their effects are probably neutral or almost neutral. These kinds of mutations account for genetic diversity.