Development of interspecific semiconsomic strains between the domesticated silkworm, Bombyx mori and the wild silkworm, B. mandarina

We constructed interspecific chromosome substituted strains using the wild silkworm, Bombyx mandarina and the domesticated silkworm, B. mori. In each developed strain, the entire diploid genome, except one targeted chromosome of B. mandarina, was substituted with B. mori chromosomes. We named these semiconsomic strains as T02 to T28, in which each strain number corresponds to the targeted chromosome number. In each of these strains, the target chromosome is heterozygous to that of B. mori. There are many phenotypic differences between these two species. Comparing the phenotypes of each strain enabled us to identify those chromosomes of B. mandarina that influenced some of its traits. We found five B. mandarina chromosomes that were correlated with the dominant phenotypes. The sibcrossing of the T02-T28 strains resulted in the identification of four B. mandarina chromosomes corresponding to the recessive phenotypes.