Mutations

Mutations are changes in the DNA that can result in no protein or an altered protein being synthesised Single gene mutations involve the alteration of a DNA nucleotide sequence as a result of the substitution, insertion or deletion of nucleotides Nucleotide substitutions include missense, nonsense, and splice site mutations. Nucleotide insertions or deletions result in frame shift mutations

Missense mutations result in one amino acid being changed for another. This may result in a nonfunctional protein or have little effect on the protein

Nonsense mutations result in a premature stop codon being produced which results in a shorter protein that can lead to genetic disorders

Splice site mutations result in some introns being retained and/or some exons not being included in the mature transcript

Nucleotide insertions or deletions result in frame shift mutations. Frame shift mutations cause all of the codes and all of the amino acids after the mutation to be changed This has a major effect on the structure of the protein produced

Chromosome structure mutations include duplication, deletion, inversion and translocation

Duplication is where a section of a chromosome is added from its homologous partner

Deletion is where a section of a chromosome is removed

Inversion is when a section of a chromosome is reversed

Translocation is when a section of chromosome is added to the chromosome, not from its homologous partner