Lethality test autosomal recessive

FIGURE 3, Diagram of autosomal recessive lethal test when the treated parent in the Pi generation is a male. Second generation (G2) cultures which fail to have flies of either sex belonging to class (b) are scored as cultures bearing one or more lethals in the second chromosome. (Key as in Fig. 1, except that the symbol + enclosed in a circle indicates a wild-type second chromosome.)... 

Perhaps the most important precaution to be observed in carrying out an autosomal recessive lethal test such as the one outlined above is to treat only the haploid gametic stages with the chemical mutagen. For if instead diploid germ cell stages are treated, recombination, which is normally absent in the male, may be induced by the treatment. Such induced recombination between homologous chromosomes could lead to deficient chromosomes, or still more complex aberrations, which could not be readily... 

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