Published online by Cambridge University Press: 14 April 2009
The melanotic tumour gene tu bw of Drosophila melanogaster has a specific suppressor su-tu. The genotypes tu bw; +su-tu and tu bw; su-tu show opposite responses, as measured by tumour penetrance, to increasing choline levels in the defined axenic medium. The three major metabolic functions of choline have been examined using additions to the axenic medium to determine which biochemical pathway(s) are different in the two genotypes. It is concluded that the opposite strain responses are due to changes in the pattern of phospholipid synthesis, and that the gene product of the su-tu gene probably functions in this area of metabolism.