Abstract
A bilateral mosaic larva for the normal and translucent skin character was found to occur spontaneously in a batch of silkworms belonging to the C-132 race. In the F1 progenies of the cross between this mosaic female and a normal J-132 male, translucent and stout larvae segregated in a ratio of approximately one to four of normal animals. This new character was expressed by a single dominant gene, and was named “Dominant obese translucent” with the gene symbol Obs. Linkage test showed that the obs gene was linked to the genes for melanism (mln) and ellipsoid egg (elp) which had been mapped in position 21.3 and 0.0. respectively, on the eighteenth linkage group. The recombination value between Obs and elp was 9.92%, Obs-mln 34.63% and elp-mln 25.38%, indicating that the Obs gene was located to the left of elp. On the basis of the present results, arrangement of gene loci on the genetic map of the eighteenth linkage group was revised as follows; Obs: 0.0, elp: 9.9, mln: 35.3.
