Mutations Flashcards
Mutations
Mutations are changes in the DNA that can result in no protein or an altered protein being synthesised.
Single gene mutations
Single gene mutations involve the alteration of a DNA nucleotide sequence as a result of the substitution, insertion or deletion of nucleotides.
Insertions and Deletions
Nucleotide insertions or deletions result in frame-shift mutations.
Frame-shift mutations
Frame-shift mutations cause all of the codons and all of the amino acids after the mutation to be changed. This has a major effect on the structure of the protein produced.
Nucleotide substitutions
Nucleotide substitutions — missense, nonsense and splice-site mutations.
Missense
Missense mutations result in one amino acid being changed for another. This may result in a non-functional protein or have little effect on the protein.
Nonsense
Nonsense mutations result in a premature stop codon being produced which results in a shorter protein.
Splice-site
Splice-site mutations result in some introns being retained and/or some exons not being included in the mature transcript.
Duplication
Duplication is where a section of a chromosome is added from its homologous partner.
Deletion (Chromosome structure mutation)
Deletion is where a section of a chromosome is removed.
Inversion
Inversion is where a section of chromosome is reversed.
Translocation
Translocation is where a section of a chromosome is added to a chromosome, not its homologous partner.
The substantial changes in chromosomal mutations
The substantial changes in chromosome mutations often make them lethal.
