Two-hybrid screening developed in a silkworm cell line from the larva or caterpillar of the domesticated silk moth, "Bombyx mori" (BmN4 cells). This system uses the GAL4 BD and the activation domain of mouse NF-κB P65. Both are under the control of the OpIE2 promoter. By changing specific amino acids by mutating the corresponding DNA base-pairs in the plasmids used, the importance of those amino acid residues in maintaining the interaction can be determined. After using bacterial cell-based method to select DNA-binding proteins, it is necessary to check the specificity of these domains as there is a limit to the extent to
Bombyx mandarina differ in karyotype from those of inland China. Domestic silkmoths are closer to the latter regarding mtDNA sequence data, and especially lack some genetic apomorphies of the northeastern "B. mandarina". Thus, the initial domestic stock came from inland China. "B. mandarina" is able to hybridize with "B. mori". Both in the wild and in a domesticated environment, females release pheromones and wait for males to be attracted and fly to them. However, "B. mori" males cannot fly. Hybridisation in the wild, therefore, inevitably means breeding between domestic ("B. mori") females and wild ("B. mandarina") males. Hybridization is possible in both