Final answer:
The genetic code is universal, present in almost all organisms, and translates genetic information into proteins. It contains 64 codons that are highly conserved, signifying all life shares an evolutionary origin. Mutations in the genetic code are rare due to the severe consequences they could provoke.
Step-by-step explanation:
The genetic code is a set of rules used by living cells to translate information encoded within genetic material (DNA or mRNA sequences) into proteins. This code is universal, meaning that with a few exceptions, virtually all organisms use the same code for protein synthesis. This universality is a strong indicator that all life shares a common evolutionary history. It is organized into 64 triplet codons, each codon made up of three nucleotides, which correspond to the 20 amino acids used in the synthesis of proteins. Interestingly, except for methionine and tryptophan, each amino acid can be encoded by more than one codon, making the code degenerate.
This characteristic conservation of codons implies that, theoretically, a piece of mRNA from one species can be placed into the cell of another species and still produce the correct protein. For example, if a purified mRNA encoding the globin protein from horses were transferred into a tulip cell, the tulip would be capable of synthesizing horse globin. The near-universal nature of the genetic code also facilitates the study of evolutionary relationships between organisms by comparing gene and DNA sequences across different species.
The conservation of the genetic code across vast biological diversity suggests that during the early stages of evolutionary history, the establishment of the genetic code likely became 'frozen' due to strong selective pressures against changes, which would be highly detrimental. This concept is often echoed by the frozen accident hypothesis, which suggests that the standard genetic code does not change because any significant alteration to it would likely be lethal to an organism.