Biology / Unit 6 Bio 1303 short lesson, about 20 seconds
Frameshift Mutations
Captions available
The idea
A frameshift mutation inserts or deletes a number of nucleotides not divisible by three, shifting the reading frame for every downstream codon.
In practice
A single nucleotide deletion near a gene's start scrambles every following codon, usually producing a nonfunctional protein.
Where people slip
An insertion or deletion of exactly three nucleotides adds or removes one codon without shifting frame — only non-multiples of three cause frameshift.
Your place on the trail
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