Maternal Effect of +<sup>lem</sup> Gene on Pterine Reductase of <i>Bombyx mori</i>

Abstract

1. In the pteridine metabolism of the silkworm, pteridine reductase acts specifically on the reaction step leading from dihydropterin to tetrahydropterin.2. The enzyme activity of the several tissues was examined in normal animals and in the mutants, lem and leml. In the integument of normal larvae the enzyme activity is strong but in that of the lemon larvae it is weak to very weak. Moreover, the integument of the lethal lemon larvae almost completely lacks this enzyme.3. In the reciprocal crosses between the +lem/leml individuals and the lem/leml individuals the maternal effect of the gene +lem on pterine reductase could be demonstrated.4. It is inferred from the experimental results of mutual transplantation of ovaries between normal and lemon larvae that the enzyme activity of the eggs is not determined by the genotype of the eggs but by that of the female in whose body the eggs develop.5. The maternal effect of +lem on the stage of death of the lethal yellow larvae is discussed.