Semaphorin-1a-like gene plays an important role in the embryonic development of silkworm,Bombyx mori

Fuyin-lethal red egg (Fuyin-lre) is a red egg mutant discovered from the germplasm resource Fuyin ofBombyx mori. The embryo of Fuyin-lrestops developing at the late stage of gastrulation due to chromosome structural variation. In this work, precise mutation sites at both ends of the mutated region were determined, and two inserted sequences with lengths of 1232 bp and 1845 bp were obtained at both ends of the mutation region. Interestingly, abmmar1transposon was detected in the inserted 1845 bp sequence.Bmmar1possesses features of theTcl/marinersuperfamily of transposable elements (TEs), which belongs to class II TEs that use a DNA-mediated "cut and paste" mechanism to transpose. This finding suggests that Fuyin-lremutation might be related to the "cut and paste" action ofbmmar1. The mutation resulted in the deletion of 9 genes in the mutation region, of which the red egg genere(BMSK0002766) did not affect embryonic development ofB.mori, and the BMSK0002765 gene was unexpressed during the early stage of embryonic development. The RNA interference results of the remaining 7 genes suggest that the semaphorin-1a-like gene (BMSK0002764) had a major contribution to the embryonic lethality of Fuyin-lre.