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Originally Posted by Textcritic
I think I understand what "duplication" is, but could you explain "insertion mutation" and "frameshift mutation"? What are these and how do they occur?
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Insertion is a new piece of DNA being added. Duplication is an existing chunk being copied. A frameshift mutation occurs when a piece of DNA is added or lost, changing the "reading frame". Nucleotides are read in groups of 3, so any addition or deletion of a number of nucleotides not divisible by 3 completely changes the translation (in most cases this is bad for the organism, but in some cases can result in something completely new).
For example if the gene sequence is originally G-A-C-T-G-A, it is read as "GAC" and "TGA". If another nucleotide is inserted at the beginning making it something like C-G-A-C-T-G-A, the first 2 sequences are "CGA" and "CTG", completely different than the original translation.
(Hopefully my explanation isn't too confusing; some of my genetics is a bit rusty since really the only genetics I do these days is looking at chemically-induced mutations leading to cancer).