Identification and characterization of the fusion transcript, composed of the apterous homolog and a putative protein phosphatase gene, generated by 1.5-Mb interstitial deletion in the vestigial (Vg) mutant of Bombyx mori

► The “vestigial wing” is a mutant of the silkworm, Bombyx mori, is controlled by the dominant gene Vg on the Z chromosome. ► A very long (1.5-Mb) deletion was found on the Vg-linked Z chromosome. ► The Vg mutant expresses the unusual fusion transcript composed of an apterous homolog gene (Bmap-A) and another upstream gene, which was generated by the chromosomal deletion. ► These results suggest that the ectopic expression of Bmap-A disturbs normal development of the wing. ► This is the first evidence showing that appropriate regulation of apterous homologs is required for normal wing development of lepidopteran insects.