The following points highlight the 3 modes of gene transfer and hereditary recombination in germs. The modes are: 1. Transformation 2. Transduction 3. Bacterial Conjugation.
Mode number 1. Transformation:
Historically, the breakthrough of change in germs preceded one other two modes of gene transfer. The experiments carried out by Frederick Griffith in 1928 suggested for the very first time that a gene-controlled character, viz. development of capsule in pneumococci, could possibly be used in a non-capsulated number of these bacteria. The transformation experiments with pneumococci fundamentally resulted in a equally significant finding that genes are constructed with DNA.
During these experiments, Griffith utilized two strains of pneumococci (Streptococcus pneumoniae): one with a polysaccharide capsule creating ‘smooth’ colonies (S-type) on agar dishes that was pathogenic. One other stress ended up being without capsule creating that is‘rough (R-type) and had been non-pathogenic. Continue reading