Sex separation by body color via a W-chromosome-linked transgene

Sex separation processes are important for commercial insect production and sterile insect techniques. Here, we describe the transgenic insertion of a DsRed expression cassette driven by the enhancer HR3 and strong promoter IE1 into the silkworm W chromosome as a dominant visible marker of sex separation. The obtained transgenic lines showed female-specific body color visible to the naked eye at the second-to fifth-instar larval, pupal and adult stages, and their performance traits were comparable to those of a nontransgenic practical silkworm va-riety. This strategy can greatly facilitate the sex separation of silkworms for male-only rearing and to obtain hybrids while avoiding sibling mating, and it can also be applied to the sex separation of other light-colored insects.

Automated summary

In this study, a DsRed expression cassette was inserted into the silkworm W chromosome as a visible marker for sex separation. The transgenic silkworms showed female-specific body color, making it easier to separate males from females. This strategy can be applied to other light-colored insects as well.