The rapid development of the genetics of higher plants
and animals in the early 20th century at first had little
effect on bacteriology and the mechanisms of inheritance
in bacteria were thought to be of quite a different kind.
What was then called bacterial ‘variation’ was recognized
but its genetic basis remained elusive, though it was suspected
by some early bacteriologists [10]. Contemporary
views began to emerge in the 1940s, when biochemical
mutants of Neurospora crassa were first isolated [11] and
the unity of genetics in the biological world was recognized.
The foundations of bacterial genetics were laid a little
later with the demonstration that bacteriophage-resistant
mutants appear spontaneously in bacterial cultures [12].