A mutation is a random change to the genetic material.
There are 2 main classes of DNA mutations:
- Point mutations - when one base pair replaces another, also called substitution.
When the gene containing the error is next replicated, at least one copy will retain the error, the incorrect base will be paired with its complementary nucleotide to complete the mutation. A substitution is only a minor mutation, as the primary structure of the protein is only changed slightly and only affects a maximum of one amino acid.
- Insertion/Deletion mutations - these cause a frameshift.
The DNA polymerase 'slips' causing it to either add or miss one or more nucleotide in the new strand. When the gene containing the error is next replicated the extra or missing base will have a knock on effect on the triplet code on the rest of the strand. The primary structure of the protein will be changed, which could be fatal.
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