Deleterious mutations in a heterozygous chromosome result in recessive lethality in silkworm semiconsomic strains

Abstract

In this study, we found two embryonic lethal mutations, t04 lethal (l-t04) and m04 lethal (l-m04), in semiconsomic strains T04 and M04, respectively. In these semiconsomic strains, the entire diploid genome, except for one chromosome 4 of the wild silkworm Bombyx mandarina, is substituted with chromosomes of the domesticated silkworm B. mori, and l-t04 and l-m04 mutations are located on B. mandarina-derived chromosome 4. The mutations responsible for the l-t04 and l-m04 were identified as the Bombyx homolog of imaginal discs arrested (Bmida) and TATA Box Binding Protein-associated factor 5 (BmTaf5), respectively. These findings indicate that both mutations were independently introduced during or after the development of semiconsomic strains. We conclude that the recessive embryonic lethality in the T04 and M04 strains is due to deleterious mutations produced in B. mandarina-derived chromosome 4. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=109 SRC="FIGDIR/small/521575v1_ufig1.gif" ALT="Figure 1"> View larger version (42K): org.highwire.dtl.DTLVardef@1c59ea3org.highwire.dtl.DTLVardef@131fbf0org.highwire.dtl.DTLVardef@93515borg.highwire.dtl.DTLVardef@1c23afe_HPS_FORMAT_FIGEXP M_FIG C_FIG