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Summary of Gene Mutations
Gene mutations are changes that take place to the sequence of nucleotides on the DNA molecule that is other than genetic recombination.Gene mutations can arise due to natural reasons, such as errors in the replication process, and these mutations are known as spontaneous mutations. Mutations also arise due to outside factors called mutagens and these are known as induced mutations. Mutations can be categorized into two groups - point mutations (also known as base pair mutations or base pair substitutions) and insertion/deletions. Point mutations themselves can either be silent mutations (no change on amino acid sequence) or they can be missense mutations (change in amino acid sequence). Insertions or deletions can lead to either frameshift mutations in which the reading frame is shifted and this causes the production of a completely different amino acid sequence. They can also cause non-frameshift mutations in which there is only a slight change in the amino acid sequence because the reading frame does not shift. All point mutations are actually non-frameshift mutations. Both point mutations and insertion/deletions can also be nonsense mutations, in which a codon is switched to a stop codon. This terminates the polypeptide prematurely and causes it to become non-functional.
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