History of genetics of the fruit fly "Drosophila melanogaster". In 1928, Frederick Griffith showed that genes could be transferred. In what is now known as Griffith's experiment, injections into a mouse of a deadly strain of bacteria that had been heat-killed transferred genetic information to a safe strain of the same bacteria, killing the mouse. A series of subsequent discoveries led to the realization decades later that the genetic material is made of DNA (deoxyribonucleic acid). In 1941, George Wells Beadle and Edward Lawrie Tatum showed that mutations in genes caused errors in specific steps in metabolic pathways. This showed that specific genes
Picric acid sample. Clinical chemistry lab testing utilizes picric acid for the Jaffe reaction to test for creatinine. It forms a colored complex that can be measured using spectroscopy. In the early 20th century, picric acid was used to measure blood glucose levels. When glucose, picric acid and sodium carbonate are combined and heated, a characteristic red color forms. With a calibrating glucose solution, the red color can be used to measure the glucose levels added. This is known as the Lewis and Benedict method of measuring glucose. Much less commonly, wet picric acid has been used as a skin dye, or