What is a mutation and how do they affect proteins?

A mutation is a change in the sequence of DNA bases in the genetic code of an organism. They're actually very common, and cause variation in a species. They are random changes, and can sometimes be inherited. There are different ways that mutations can change the DNA base sequence:Insertions - a new base is inserted into the DNA base sequence where it shouldn't be. For example, TACTAGA becomes TACTAAGA.Deletions - a random base is deleted from the DNA base sequence. For example, TACTAGA becomes TACTGA.Substitutions - a random base in the DNA base sequence is changed to a different base. For example, TACTAGA becomes TACTACA.DNA base sequences are 'read' in groups of 3 and code for different amino acids. Both insertion and deletion mutations can have 'knock on' effects and change multiple amino acids, whereas a substitution mutation may only change one amino acid. Because amino acids make up proteins, a change in amino acid can change the protein produced - with different effects!Remember - multiple different combination of 3 DNA bases can code for the same amino acid, so a change may not produce a different amino acid (and therefore protein)!