The effects of chloroform on three strains (Eth, Quick Sand, and bw; st; svn) were investigated genetically. Adult flies at 24 hours of age were anesthetized with chloroform for 0.5 and 1.0 minute, and mortalities were assessed 4 days later. The Eth strain was resistant and the Quick Sand and the bw; st; svn strains, susceptible to the chloroform. Reciprocal crosses between the Eth and the bw; st; svn strains showed that the resistance to chloroform was completely dominant over sensitivity and that maternal or cytoplasmic effects were negligible. A major gene(s) with respect to chloroform resistance is located on the X-chromosome, and a minor gene(s), on the second chromosome. We reported that the Eth strain was more resistant to ether than the Quick Sand and the bw; st; svn strains. Thus, it can be said that a cross-resistance to ether and chloroform is found in the Eth strain. The resistance to ether, as well as to chloroform, is a completely dominant trait with no maternal or cytoplasmic factors. However, the locus of the major gene(s) for the ether resistance is 61± on the third chromosome, and the minor genes are on both the X-and the fourth chromosomes. Therefore, resistances to ether and to chloroform are controlled by different genes. This suggests that the mechanisms of resistance to ether and to chloroform are different. © 1979, The Genetics Society of Japan. All rights reserved.
