- A mutation is an unpredictable change in the genotype of a cell that results from damage to, or imperfect replication of, the DNA, or from faulty operation of mitosis or meiosis.
- Can be a gene mutation or chromosome mutation.
- Mutation is a rare event.
- Mutation takes place in a single cell, but cannot usually be detected until the mutant cell is replicated and a distinctive phenotype has been produced.
- Some chemicals, mutagens, increase the chance of mutation because they react with DNA or interfere with replication.
- Some types of radiation, such as X-rays, cause mutation by damaging DNA.
- A gene mutation affects the nucleotide sequence of a section of DNA so that the triplet code for the primary structure (amino acid sequence) of the polypeptide coded by the gene is changed.
- One or more nucleotides may be deleted from, or added to, the sequence. This alters the reading frame of the triplet code, altering all subsequent triplet codes.
- One nucleotide may be substituted for another, producing a different triplet code which may code for a different amino acid or be…