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
Homogentisic acid Homogentisic acid Homogentisic acid (2,5-dihydroxyphenylacetic acid) is a phenolic acid usually found in "Arbutus unedo" (strawberry-tree) honey. It is also present in the bacterial plant pathogen "Xanthomonas campestris pv. phaseoli" as well as in the yeast "Yarrowia lipolytica" where it is associated with the production of brown pigments. It is oxidatively dimerised to form hipposudoric acid, one of the main constituents of the 'blood sweat' of hippopotamuses. It is less commonly known as melanic acid, the name chosen by William Prout. Accumulation of excess homogentisic acid and its oxide, named alkapton, is a result of the failure of the enzyme