Normal DNA Strand DNA : TAC AAA GGA CGA GTA GTT TAA GCA AGA ATT mRNA: AUG UUU CCU GCU CAU CAA AUU CGU UCU UAA Protein: Met-Phe-Pro-Ala-His-Glu-Ile-Arg-Ser-Stop

Mutation Mutation – Any change in the DNA base sequence which leads to a change in a protein. Sometimes mutation are beneficial, but they usually lead to non-functioning or incorrectly functioning proteins.

Point Mutation – One base in sequence is changed Original DNA: TAC AAA GGA CGA GTA GTT TAA GCA AGA ATT Original Protein: Met-Phe-Pro-Ala-His-Glu-Ile-Arg-Ser-Stop 4th triplet in DNA, first base C changed to G Mutated DNA: TAC AAA GGA GGA GTA GTT TAA GCA AGA ATT Incorrect mRNA: AUG UUU CCU CCU CAU CAA AUU CGU UCU UAA Mutated Protein: Met-Phe-Pro-Pro-His-Glu-Ile-Arg-Ser-Stop The 4th amino acid is proline instead of alanine

Point Mutation

Frameshift Mutation – One base added or deleted from the DNA sequence Original DNA: TAC AAA GGA CGA GTA GTT TAA GCA AGA ATT Original Protein: Met-Phe-Pro-Ala-His-Glu-Ile-Arg-Ser-Stop 2nd triplet in DNA, first base A deleted Mutated DNA: TAC AAG GAC GAG TAG TTT AAG CAA GAA TT Incorrect mRNA: AUG UUC CUG CUC AUC AAA UUC GUU CUU AA Mutated Protein: Met-Phe-Leu-Leu-Ile-Lys-Phe-Val-Leu After the second amino acid, the protein is completely different

Frameshift Mutation

The bottom line about DNA… No DNA = No Protein = No Cells = No Life Reproduction is all about passing DNA from one cell to another and from one generation of organisms to the next