Amber mutation

Amber mutation is a type of nonsense mutation in the genetic code of an organism. Named after its discoverers, Harris Bernstein, Richard J. Epstein and Richard Bolle, who were at the time at the University of California, Berkeley, the term "amber" was derived from their combined initials (Am, Ber).

Overview

An amber mutation is a specific type of point mutation where a nucleotide triplet within DNA that usually codes for an amino acid is changed to the specific stop codon known as an "amber" stop codon. This results in a prematurely shortened, incomplete, and usually nonfunctional protein product.

Mechanism

The amber mutation occurs when a nucleotide triplet within DNA is changed to the amber stop codon (UAG). This can occur through a variety of mechanisms, including base substitution, deletion, or insertion. When the ribosome encounters the amber stop codon during protein synthesis, it halts the process, resulting in a truncated protein.

Effects

The effects of amber mutations can vary widely, depending on the location of the mutation within the gene and the role of the affected protein in the organism. In some cases, the truncated protein may still be partially functional, while in others, the mutation can result in a completely nonfunctional protein. This can lead to a variety of genetic disorders, including some forms of cancer and genetic diseases.

Suppression

Amber mutations can be suppressed by a class of tRNA molecules known as amber suppressors. These molecules are able to recognize the amber stop codon and insert an amino acid at that position, allowing the protein synthesis to continue and potentially restoring some or all of the protein's function.

See also

• Nonsense mutation
• Stop codon
• Genetic code
• Amber suppressor