Nonsense mutations work primarily by changing the sequence of DNA, which produces new proteins that are either nonfunctional or defective. Nonsense mutations are point mutations that introduce new stop codons prematurely into the part of genes that encode proteins. Mutations may change the DNA sequence of cells and occur in several different varieties.
Stop codons serve important roles in controlling the proper production of proteins. Normally, these codons instruct ribosomes to stop making proteins when there are too many of one variety. However, nonsense mutations arise when codons make faulty or partial proteins, which in turn do not function as they are supposed to.