Genetic Code Cracking

The work of Marshal Nirenberg and Heinrich Matthaei between 1961 and 1966 resulted in the cracking of the genetic code [18]. They demonstrated that a codon consisting of three nucleotide bases determines each of the 20 amino acids. 

The Genetic Code Was Cracked Using Artificial mRNA Templates... 

Consolidation of the results from many experiments permitted the assignment of 61 of the 64 possible codons. The other three were identified as termination codons, in part because they disrupted amino acid coding patterns when they occurred in a synthetic RNA polymer (Fig. 27-6). Meanings for all the triplet codons (tabulated in Fig. 27-7) were established by 1966 and have been verified in many different ways. The cracking of the genetic code is regarded as one of the most important scientific discoveries of the twentieth century. 

Scientists set out to determine the specific codons for each amino acid. In 1961, Marshall Nirenberg prodnced the first crack in the genetic code (the collection of codons that specify all the amino acids fonnd in proteins). He showed that poly(U), a polynucleotide in which all the bases are uracil, produced polyphenylalanine in a cell-free protein-synthesizing system. Thus, UUU must be... 

The basis is the genetic code, which describes how various combinations of nucleotides (of which there are only four types in DNA or RNA) can be interpreted as individual amino acids (of which there are 20 types, plus two special atypical ones, as described in Chap. 3). The cipher of the genetic code was cracked in the 1960s. 

Discovering the exact makeup of human dna has been termed cracking the genetic code, and that is what generated so much excitement in 2000. 

The idea of LUCA started to crystallize in 1960s, when genetic code was cracked and turned out to be universal in all of the biosphere (with some marginal variations) — that was naturally interpreted as a sign of common ancestry. Now the idea of LUCA seems well established, although genetic and other features of it are not yet clear. 

---