大象传媒

Point mutations

Substitutions result in a change that only affect one codon. This is known as a point mutation. The resulting mutation can be one of three types:

MissenseNonsenseSplice-site
change the codon so that a different amino acid is producedchange the codon from an amino acid to a stop codonaffect the boundaries between exons and introns (splice sites)
may result in the shape of the protein changing so that it cannot carry out its functionresults in a shorter protein being producedcan prevent splicing at that site
some changes in amino acid may not have any significant effectshortened protein is generally non-functional or its function is affecteda very different protein is made due to the post transcriptional processing as some introns may be included or some exons removed
Missensechange the codon so that a different amino acid is produced
Nonsensechange the codon from an amino acid to a stop codon
Splice-siteaffect the boundaries between exons and introns (splice sites)
Missensemay result in the shape of the protein changing so that it cannot carry out its function
Nonsenseresults in a shorter protein being produced
Splice-sitecan prevent splicing at that site
Missensesome changes in amino acid may not have any significant effect
Nonsenseshortened protein is generally non-functional or its function is affected
Splice-sitea very different protein is made due to the post transcriptional processing as some introns may be included or some exons removed