Question

What is wobble theory?

Answer 1

Wobble theory or hypothesis was given by Francis Crick. It states that base pairing can occur in nitrogen bases in 1 and 2 positions of the codon and the corresponding bases in the anticodon. Wobble base pairs are fundamental in RNA structure and are usually said to be critical for translation of the genetic code.

Complete answer:
Francis Crick proposed "The Wobble Hypothesis", which explained the possible cause of degeneracy of the codons. There are more than one codon that codes for one amino acid. This is called degeneracy of the genetic code.
According to this hypothesis, only the first two bases of the codon have a precise pairing with the base of the anticodon of tRNA, while the pairing for the third base pair of codon and anticodon may Wobble. This phenomenon permits a single tRNA to recognize more than one codon and therefore around 61 codons for amino acids are there, but the number of tRNA is far less which is due to wobbling.
This theory states that the base at the 5' end of the anticodon is not spatially confined as the other two bases, allowing it to form hydrogen bonds with any of several bases located at the 3'end of a codon.
The Wobble base pairing takes place in consideration of the following :
The four wobble pairs are guanine- uracil, hypoxanthine- uracil, hypoxanthine- adenine, hypoxanthine - cytosine.
A wobble pair is a pairing that takes place in two nucleotides in RNA molecules that do not follow Watson- Crick base pair rule.
Inosine displays true wobbling where the first nucleotide in the anticodon then any of the three bases in the original codon can be matched with the tRNA.
In order to maintain consistency in Nomenclature, "I" is used for hypoxanthine because it is the nucleobase of inosine.
Crick's hypothesis predicted that the initial two ribonucleotides of triplet codes are more critical than the third member in attracting the right tRNA.

Note:
Wobble base pairs are fundamental in RNA secondary structure. Wobbling allows faster dissociation of tRNA from mRNA and for protein synthesis. Existence of wobbling minimizes the damage that is caused by misreading of the code. It's base pair is thermodynamically more stable than Watson - Crick base pair.