MBG 2040 Lecture Notes - Lecture 4: Mutation, Mutagen, Dna Replication

• School: University of Guelph
• Department: Molecular Biology and Genetics
• Course: MBG 2040
• Professor: Jim Uniacke

Document Summary

Mutation: genetic variability for evolution: mutations are changes in dna; occur spontaneous in germ-line or somatic cells; can also be induced. Inherited changes in genetic material: provide new genetic variation that allow organisms to evolve. Mutation and evolution: mutation is source of all genetic variation, recombination mechanisms rearrange genetic variability into new combinations, natural selection preserves combinations best adapted to existing environment, without mutation, all genes would exist only in one form. Alleles would not exist, and classical genetic analysis would not be possible: most important- populations of organisms would not be able to evolve and adapt to environmental changes. Spontaneous mutations: occur without known cause due to inherent metabolic errors or unknown agents in environment (also induced but by unknown cause) Induced mutations: result from exposure of organisms to mutagens- physical and chemical agents that cause changes in dna, such as ionizing irradiation, uv light, or certain chemicals.