Question

How did scientists reach the conclusion that genetic code is in the form of triplets?

Answer 1

It was a known fact that there are four kinds of bases and 20 amino acids. Scientist proposed that coding
units cannot be single as it will encode only 4 amino acids and if coding unit is paired it will encode only 16 amino
acids (4² = 16). George Gamow proposed that if 20 amino acids are to be coded by 4 bases, then the code should be made up of three nucleotides. 4³ = 64, so, the codon was proposed to be triplet.
Among the 64 codons, 61 code for amino acids and 3 of them do not. Also many codons can code for same amino acid.