 | Study Outline
(See related pages)
- Consequences of Mutation
- Gene mutations are molecular changes in the DNA sequence of a gene
- Gene mutations can alter the coding sequence within a gene
- Gene mutations are also given names that describe how they affect the wild-type genotype and phenotype
- Gene mutations can occur outside of the coding sequence and still influence gene expression
- DNA sequences known as trinucleotide repeats may cause mutation
- Changes in chromosome structure can affect the expression of a gene
- Mutations can occur in germ line or somatic cells
- Occurrence and Causes of Mutation
- Spontaneous mutations are random events
- Randomly occurring mutations can give an organism a survival advantage
- Mutation rates and frequencies are ways to quantitatively assess mutation in a population
- Spontaneous mutations can arise by depurination, deamination, and tautomeric shifts
- X-rays were the first environmental agent shown to cause induced mutations
- Mutagens alter DNA structure in different ways
- Testing methods can determine if an agent is a mutagen
- DNA Repair
- Damaged bases can be directly repaired
- Base excision repair removes a damaged base
- Nucleotide excision repair systems remove segments of damaged DNA
- Mismatch repair systems recognize and correct a base pair mismatch
- Damaged DNA can be repaired by recombination
- Actively transcribed DNA is repaired more efficiently than nontranscribed DNA
- Damaged DNA may be replicated by translesion DNA polymerases
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