Final answer:
A change in a single amino acid may not have a noticeable effect on the protein due to neutral or synonymous mutations. These mutations can result in the same amino acid being encoded or a different codon encoding the same amino acid. An example is the silent mutation, where the codon is changed without altering the protein's function.
Step-by-step explanation:
When a change in a single amino acid does not have a noticeable effect on the protein, it means that the mutation is either neutral or synonymous. Neutral mutations do not impact the structure or function of the protein, while synonymous mutations result in a different codon that still encodes the same amino acid. These mutations may occur due to redundancy in the genetic code, where multiple codons can code for the same amino acid.
For example, a silent mutation is a type of synonymous mutation where the codon is changed to another codon that still encodes the same amino acid. Since this mutation does not change the protein product, it can only be detected through gene sequencing.
In some cases, an amino acid change may not have a noticeable effect on the protein's structure and function, such as the case of hemoglobin in individuals with sickle cell trait. The substitution of valine for glutamic acid at a specific position in the hemoglobin protein does not significantly affect its ability to carry oxygen.