Step 1: Understanding the Problem:
The genetic code is the set of rules by which information encoded in genetic material is translated into proteins.
A "triplet code" means that three consecutive nucleotides (a codon) specify a single amino acid.
Step 2: Approach and Formula:
Trace the historical timeline of discoveries related to the genetic code to identify who provided the very first experimental proof of its triplet nature.
Step 3: Detailed Explanation:
While George Gamow first proposed mathematically that the genetic code should be a triplet, Francis Crick and his colleagues provided the first robust experimental evidence.
Crick performed experiments using frameshift mutations on the T4 bacteriophage.
He showed that inserting or deleting a single or double base pair severely disrupted the reading frame, but inserting or deleting exactly three base pairs restored the reading frame and produced a functional protein.
Nirenberg, Matthaei, and Khorana came later to synthesize RNA and decipher which specific triplets mapped to which amino acids.
Step 4: Final Answer:
The first experimental evidence was provided by Crick.