Скачать или смотреть Class 12 II Molecular basis of inheritance ll Search of genetic material ll by Kanupriya sharma

Friedrich Meischer in 1869 identified DNA present in the nucleus as an acidic substance and named it as ‘Nuclein’
Frederick Griffith in 1928 demonstrated in the infected mice that some “transforming principle” gets transferred from heat-killed S-strain of Streptococcus pneumoniae to R-strain, enabling it to make the smooth polysaccharide coat, hence it becomes virulent
Oswald Avery, Colin MacLeod and Maclyn McCarty determined the biochemical nature of “transforming principle” and discovered that only DNA is responsible for the transformation
Hershey and Chase in 1952 proved that DNA is the genetic material. They infected the bacteria E. coli with bacteriophages grown in radioactive phosphorus (32P) which labels DNA of the bacteriophage, which gets transferred to the bacteria cells and radioactive sulfur (35S), which labels the protein coat of the bacteriophage, hence radioactivity is not detected in the bacterial cell