A visible dominant marker for insect transgenesis

Transgenesis of most insects currently relies on fluorescence markers. Here we establish a transformation marker system causing phenotypes visible to the naked eye due to changes in the color of melanin pigments, which are widespread in animals. Ubiquitous overexpression of arylalkylamine- N -acetyl transferase in the silkworm, Bombyx mori , changes the color of newly hatched first-instar larvae from black to a distinctive light brown color, and can be used as a molecular marker by directly connecting to baculovirus immediate early 1 gene promoter. Suppression of black pigmentation by Bm- arylalkylamine- N -acetyl transferase can be observed throughout the larval stages and in adult animals. Alternatively, overexpression in another gene, B. mori β-alanyl-dopamine synthetase ( Bm-ebony ), changes the larval body color of older instars, although first-instar larvae had normal dark coloration. We further show that ectopic Bm- arylalkylamine- N -acetyl transferase expression lightens coloration in ladybird beetle Harmonia axyridis and fruit fly Drosophila melanogaster , highlighting the potential usefulness of this marker for transgenesis in diverse insect taxa.