Question

Wobble hypothesis for genetic code was given by
A) Bernfield and Nirenberg
B) Crick
C) Creighton
D) Hedges

Answer 1

Hint:To explain the possible cause of degeneracy of codons,“the Wobble hypothesis”.
Theory is proposed.Having more than one codon for one amino acid is known as degeneracy.

Complete answer:
First we should know about the Wobble hypothesis to answer this question. According to this theory, just the first two codon bases have a specific pairing with the tRNA anticodon bases, whereas the pairing can wobble between the third codon bases and the anticodon bases. The phenomenon causes more than one codon to be recognised by a single tRNA. Therefore, while there are 61 amino acid codons, the tRNA number is much smaller (around 40) due to wobbling.
Now, let us find the solution from the options-
- The Wobble theory is based on the fact that the tRNA anticodon base in the first place is normally an irregular base, such as inosine, tyrosine, pseudouridine, etc.
- At the third position of the codon on mRNA, these irregular bases pair with far more than one form of nitrogen base; inosine (I) may pair with A, C or U. T
- This base is referred to as the Wobble base, which is found in anti-codon position 1 and codon position 3.
- For one amino acid, more than one codon occurs. This is considered genetic code degeneracy.
-In 1966, Francis Crick suggested "the Wobble theory" to describe the probable cause of codon degeneracy.

Thus, the correct answer is option (B) Crick.

Note:In RNA molecules, a wobble base pair is a conjunction of two nucleotides that does not obey the rules of the Watson-Crick base pair. Hypoxanthine-adenine (I-A) guanine-uracil (G-U), hypoxanthine-Uracil (I-U), and hypoxanthine-cytosine (I-C) are the four main wobble base pairs.