The early years of molecular biology: personal recollections

The early years of molecular biology were characterized by a strong interaction between theory and experiment. This included the elucidation of the structure of DNA itself; genetic fine structure, recombination and repair; DNA replication; template-directed protein synthesis; the universality of the triplet genetic code, and the co-linearity of the DNA sequence of structural genes and the sequence of amino acids in proteins. The principle of co-linearity was later modified when split genes were discovered. It is suggested that accurate splicing of gene transcripts might also be template directed. In 1958 Crick proposed a 'central dogma' of molecular biology stating that information could not be transmitted from proteins to DNA. Nevertheless, proteins can chemically modify DNA, and this is now known to have strong effects on gene expression.