MICROBIAL GENETICS

In prokaryotes the method of cell division differs from that of eukaryotes. No meiosis or mitosis occurs in prokaryotes because of lack of nucleus. In contrast, in prokaryotes and a few eukaryotic microorganisms most of genetical and molecular works, have been carried out because of easy in handling, fast growth rate, immediate observable characters under any change in conditions and least complex life forms.

Like higher plants and animals, bacteria and the other protists transmit characters to their progenies and in onward generations. Apart from inheritance of characters they also show variability in progenies. These changes are reffered to as phenotype (morphological changes) and genotype (genetic changes). The genotype always remains constant however changes occur through mutation which results in morphological changes or phenotypes in progenies.

In addition, the phenotypic expression depends on the environmental conditions as well. Example is phenotypic changes in agrobacterium radiobacter takes place if it is grown on two different growth media. Mucoid colonies are formed on source salt medium and non-mucoid colonies develop on trypticase soy-agar medium. Secondly yeast produces ethanol when grown in a oxygen deficient conditions, and it is increased its bioms and does not produce ethanol when grown in the presence of sufficient oxygen.