On the content of nucleic acids in the posterior division of the silk gland in the tetraploid and mosaic silkworm, Bombyx mori

Abstract

The DNA content in the cell of the posterior division of the silk gland was found to be twofold in the tetraploid silkworm as compared with the diploid one. However, no distinction was found between them in the RNA content. The cells of the silk gland of the tetraploid silkworm were half as many as those of the diploid silkworm in number. Therefore the amount of silk production by the tetraploid silkworm was inferior to the diploid one.
The DNA and RNA in the midgut of tetraploid silkworm were equal in quantity to those of the diploid one. From these facts, it can be considered that the number of cells of the midgut of the tetraploid silkworm decreased to a half of the diploid one.
There was a definite difference in the RNA content in the posterior division of the silk gland of the mosaic silkworm according to the genotypes of the silk glands. In the silk gland having the genotype KN or K 6 the RNA content was large, but in the silk gland having the genotype KK it was small, as shown in both cases of the control silkworms. The amount of RNA in the posterior division of the silk gland of genotype KK side of the mosaic silkworm was larger than that of the female silkworm used for hybridization, KATSUKI's mosaic.
The silk gland of genotype KN side of the mosaic larva had smaller amount of DNA than that of a hybrid of Nichi 124 and KATSUKI's mosaic, which was also having genotype KN. The silk gland of genotype KK side of the mosaic larva had larger amount of DNA than that of the female silkworm used for hybridization, KATSUKI's mosaic.