PENETRANCE AND EXPRESSIVITY OF TUMOROUS HEAD IN DROSOPHILA MELANOGASTER AND RELATIVE VIABILITY OF FLIES CARRYING TUMOROUS HEAD GENES

Abstract

N hereditary head abnormality in Drosophila nic~lmopzstcr arid the ge-A netic niechanisin which controls it were discussed by GARDNER and WOOLF (1949) and' GARDNER (194811, lY49). The itiflueiice of temperature treatments on the expression of the character was described by GARDNER a i d WOOLF (1950) and Wooiic (1949). The objective of the present paper is to discuss the penetrance aiid espressivity of the character aiid tlie relativc viability of the flies carrying the genes upon which the expression of the trait is dependent.