A mutation is a change in the DNA sequence, which is like an instruction manual for making proteins. DNA is made up of four chemical bases: A, T, C, G. Mutations can alter the instructions for making proteins and affect how they function.
Point Mutation:
A single nucleotide (DNA "letter") changes.
Example: If AAG changes to AAC, it might lead to a different amino acid or no effect.
Nonsense Mutation:
A mutation creates a "stop" signal, cutting the protein short.
Example: Normal TAC-GCC-TTT mutates to TAC-GCA-TAG, introducing a stop signal (TAG) too early.
Missense Mutation:
One nucleotide changes, resulting in the wrong amino acid.
Example: AAG (codes for lysine) mutates to GAG (codes for glutamic acid).
Deletion Mutation:
One or more nucleotides are removed.
Example: ATG-GCC-TAA becomes ATG-CCT-AA, shifting the sequence.
Insertion Mutation:
Extra nucleotides are added.
Example: ATG-GCC-TAA becomes ATG-AGC-CTA-A, altering the reading frame.
Frameshift Mutation:
Insertions or deletions shift how DNA is read in groups of three (codons).
Example: Normal ATG-GCC-TTT-TAA becomes ATG-CCT-TTT-AA, leading to a completely different protein.
Some mutations are beneficial and can lead to helpful traits.
Others cause diseases like cancer or sickle cell anemia.
Some mutations are "silent" and have no noticeable effects.
Mutations can have big or small impacts depending on where and how they occur!