DNA and the Genome - Mutations Flashcards
deletion
single gene mutation
gene mutation involving the loss of a nucleotide from the DNA sequence
frameshift mutation effect
deletion
chromosome mutation
loss of a segment of chromosome consisting of one or more genes
ABCDE –> ADE
insertion
single gene mutation
gene mutation involving the addition of an extra nucleotide to the DNA sequence
duplication
chromosome mutation
a section of a chromosome attaches to its homologous partner
ABCDE –> ABCBCDE
mutation
- a random change in an organism’s DNA, either the quantity or structure is altered
- mutations occur at random and are rare
inversion
chromosome mutation
reversal of gene order of a segment of chromosome as a result of two breaks in the same chromosome
ABCDE –> ADCBE
single gene mutation
alteration of a DNA
nucleotide sequence as a
result of:
- substitution,
- insertion or
- deletion of nucleotides
translocation
chromosome mutation
transfer of a segment of genes from one chromosome to another non-homologous chromosome
substitution
single gene mutation
gene mutation involving the exchange of one nucleotide for another in the DNA sequence
substitution mutations
types and effect
- missense - the altered code codes for a protein that makes sense but not the original sense; protein could be non-functional or have little affect
- nonsense - the substitution codes for a stop codon; polypeptide chain will be shorter either not functional or a different protein
- splice site - mutation occurs in area which marks the start or end of an intron; could mean introns are left in mature transcipt or exons are left out causing disfunctional proteins
chromosome structure mutation
definition
alteration to whole sections of chromosomes, affecting several genes, as a result of:
- duplication,
- deletion,
- inversion or
- translocation
mutant
an individual whose genotype expresses a mutation
organism affected by a mutation
