What are the stop codons? What is the role of a stop codon?
1 Answer
Dec 15, 2017
Three 'stop' codons on RNA are:
UAA,
UAG,
UGA.
Explanation:
- Stop codons signal end of translation because these are 'nonsense' i.e. they do not represent any amino acid. Hence when such a codon is exposed on surface of ribosome during translation, the translation stops.
- It is interesting to note that scientists in Caltech discovered phenomenon of nonsense mutations first (in T4 viral particles) and later concluded about the sequence of triplet bases of nonsense codons.
- It was called 'amber' mutation, after the name of one particular laboratory technician/student Harris Bernstein who helped in isolation of mutants: The last name in German means colour amber.
- Nobel laureate Sydney Brenner concluded that 'amber' mutation is UAG. Two more stop codons were soon detected: UAA and UGA. To match with 'amber' the other two were also named after colours, respectively as ochre and opal.
