GEN-3000 Lecture Notes - Lecture 9: Tobacco Mosaic Virus, X-Ray Crystallography, Dna Extraction
Document Summary
Early on, genetic material had some known properties: must be capable of being replicated faithfully, must encode complex information, must be able to express that information to yield phenotype, must have variation as a result of mutation. 1869: miescher discovers nuclein (dna) in the nuclei of white blood cells. Miescher-studied pus, isolated nuclei, contained slightly acid material -named in nuclein. 1887: recognition that nucleus is the physical basis of heredity. Late 1800s: kissol determines that dna contains nitrogenous bases. Nucleotide (most basic component of dna)-sugar, phosphate, and base. Also proposed tetranucleotide theory-dna is made up of units of four bases in a fixed sequence. Dna too regular to encode info (protein is genetic material!) Virulent strain has polysaccharide coat: smooth coat (s)- cause pneumonia in mice. 1944: avery, macleod, and mccarty-isolated the transforming principle. Their experiment told them that the dna was the transforming principle.
