In this article we will discuss about the biochemical evidence that genes are made of DNA. Quantitative estimations of DNA carried out on various organisms revealed the following constant features, providing additional support for DNA as the genetic material: 1. The amount of DNA per cell in an organism or a given species is remarkably constant and cannot be altered [...]
Griffith was working with the micro-organism Diplococcus pneumonia also called Pneumococcus, a bacterium causing pneumonia. Some strains of this bacterium have a smooth polysaccharide capsule which causes disease and are designated as virulent S type strains. In a mutant strain the bacteria have no capsule, and when grown on the surface of an agar plate, they form small rough colonies [...]
In this article we will discuss about the genomes in chloroplast DNA and mitochondria DNA. The phenomenon of extra-nuclear inheritance based on transmission of visible phenotypes through mitochondria and chloroplasts. Studies in the 70s revealed presence of DNA in these organelles. Both mitochondria and chloroplasts are present only in cells of lower and higher eukaryotic organisms. Detailed studies established that [...]