A brief history of microbial genetics

Genetic research on yeast, Neurospora and paramecium began in the mid-1930s, but at that time, the research objects were limited to microorganisms capable of sexual reproduction, and the research topics were mostly limited to gene separation, linkage and recombination. American geneticist G.W. Bedell and biochemist E.L. Tatum began to understand and use the advantages of microorganisms for genetic research. They initially tried to clarify the original function of genes by studying the inheritance of pigments in the compound eyes of Drosophila. Although some progress has been made, it is not ideal, so they used Neurospora as the research material to study the role of genes in amino acid biosynthesis. The reasons are as follows: ① The molecular structure and biosynthetic pathway of Drosophila compound eye pigment are complex, so it is difficult to obtain a large number of pigments; ② The molecular structure or biosynthesis of amino acids is simpler than that of pigments; ③ Neurospora is easy to obtain its metabolites by mass culture; (4) Just as the research on the compound eye pigment of Drosophila must obtain the mutant that can't synthesize pigment, in order to study the role of genes in amino acid synthesis, it is necessary to obtain the mutant that can't synthesize amino acid. To do this, the organism studied must be able to synthesize all amino acids by itself, and Neurospora is such an organism. ⑤ The research on gene isolation, linkage and recombination of Neurospora has been established. It is reported that gene mutation in microorganisms is induced by radiation.