MBG 2040 Final: Chapter 13- Mutation and repair of DNA
Document Summary
Mutation: the ultimate source of genetic variability required for evolution. Mutation- a change in the genetic material of an organism: the process by which the change occurs. Mutant- an organism that exhibits a novel phenotype. Types of mutations- changes in chromosome number and structure: point mutations- changes at specific sites in a gene (substitution, insertion or deletion) Mutation is the ultimate source of all genetic variation. Recombination mechanisms re-arrange genetic information into new combinations. Natural selection preserves the combinations that are best adapted to the existing environment. Mutations alter the nucleotide sequences of genes in several ways: 1) the substitution of a single base pair for another 2) the deletion or insertion of one or a few base pairs (collectively called indel mutation) Tautomeric shifts- when a hydrogen atom jumps from one position to the next. Errors resulting from dna replication: tautomeric shifts affect base pairing.