4.3.1 Genetic Mutations

Effects of Mutations:

• A mutation can alter the sequence of amino acids in a protein, potentially affecting its structure and function.
• Due to the degenerate nature of the genetic code, some mutations may not change the amino acid sequence and have no impact on the protein.
• However, certain mutations can result in a non-functional protein or have harmful effects on the organism.

Types of Mutations:

1. Substitution:

• Definition: When a nucleotide in the DNA sequence is replaced by another.
• Effects:
• May have no effect if the codon still codes for the same amino acid (silent mutation).
• Can lead to a different amino acid being incorporated (missense mutation), which may alter the protein's structure or function.
• If a substitution results in a stop codon (nonsense mutation), the protein may be truncated and non-functional.

2. Deletion:

• Definition: When a nucleotide is removed from the DNA sequence.
• Effects:
• Causes a frameshift mutation, altering the way codons are read from the point of deletion onward.
• This usually results in a completely different amino acid sequence, leading to a non-functional protein.