title: Effects of dose on the induction of  dominant-lethal mutations and heritable translocations with ethyl methanesulfonate in male mice.
abstract: Genetic damage by ethyl methanesulfonate (EMS) in male mice was measured at doses ranging from 50 to 300 mg/kg with dominant-lethal mutations and reciprocal translocations as endpoints. No appreciable increase in dominant-lethal mutations was detected following a dose of 100 mg/kg. Dominant lethals induced by EMS were convincingly detected only after a dose of 150 mg/kg, but in the translocation experiment an increase in the genetic effect was detectable at the 50 mg/kg dose. It is likely that dominant lethals had also been induced at the 50 and 100 mg/kg doses, but were not detected due to the relative insensitivity of the dominant..lethal procedure. Thus, for detection of low levels of EMS-induced chromosome breakage, translocations are a much more reliable endpoint than are dominant-lethal mutations. A procedure for large-scale screening of induced translocations is described.-The dominant-lethal dose-response curve, plotted on the basis of living embryos as a percentage of the control value, is clearly not linear as it is markedly concave downward. Similarly, the translocation dose-response curve showed a more rapid increase in the number of translocations with dose than would be expected on the basis of dose-square kinetics. It is clear for both of these endpoints that the effectiveness of EMS in inducing chromosome breakage is proportionately much lower at low doses.
mesh_terms: D000818:Animals; D002869:Chromosome Aberrations; D004305:Dose-Response Relationship, Drug; D005260:Female; D005298:Fertility; D005799:Genes, Dominant; D005804:Genes, Lethal; D014644:Genetic Variation; D006579:Heterozygote; D007248:Infertility, Male / Q000235:genetics; D008297:Male; D008698:Mesylates / Q000008:administration & dosage* / Q000494:pharmacology; D051379:Mice; D009154:Mutation; D012641:Selection, Genetic; D014178:Translocation, Genetic
chemical_list: D008698:Mesylates