DNA Mutability - Feb 8 Flashcards
Mutation
heritable and stable change in DNA sequence
In mutant DNA, both strands are
mutated
There is no molecular difference between mutation and
genetic polymorphism (generally positive connotation)
Without DNA repair, spontaneous DNA damage would
change genomic sequences too rapidly for life
DNA damage is repaired by multiple pathways because
repair enzymes must recognize different chemical alterations
DNA damage only becomes a mutation when repair fails before
replication creates a new stable, heritable, double-stranded sequence
Differences in sequence (genotype) may cause
differences in phenotype
Point Mutations are
single nucleotide changes
When a point mutation occurs in a protein-coding sequence, the resulting protein
might have altered function
Types of Point Mutations
Wildtype, Silent, Missense, Nonsense
single nucleotide changes means _ is present
Point Mutations
Frameshift Mutation
insertion or deletion of a # of nucleotides that is not divisible by 3 (insertion of 1, 2, or 4 nucleotides) - results in reading frame shift and altered amino acids following the frameshift
Nonmutant mutation
expresses normal transcription + translation ex.wildtype
Synonymous mutation
nucleotide substituion that doesn’t change amino acid (ex.silent)
nonsynonymous mutation
nucleotide substitution that changes amino acid is nonsynonymous mutation (ex. missense mutation)
