Abstract

In the silkworm, Bombyx mori, no glue egg is mainly controlled by Ng (No glue)gene, which is located on the 12th chromosome. Owning to a lack of crossing over in females, reciprocal backcrossed F₁ (BC₁) progenies were used for linkage analysis and mapping of the Ng gene based on the simple sequence repeats (SSR)linkage map using silkworm strains H9 and P50, which are Ng mutant and normal to egg, respectively. The Ng gene was found to be linked to three SSR markers.Using a reciprocal BC₁M cross, we constructed a linkage map of 36.4 cM, with Ngmapped at 15.9 cM and the nearest SSR marker at a distance of 7.4 cM. Based on fine genome map of domesticated silkworm (B. mori), the result of Kaikoblast show that the physical distance between the near markers (containing Ng gene) is 181.7 Kb. Further analysis show that BGIBMGA005833, BGIBMGA005835 and BGIBMGA005836 are closer to Ng, and the BGIBMGA005835 is nearest to Ng,which physical distance is 44 Kb.

Key words: Gene location, linkage analysis, microsatellite, Ng, silkworm.

Abbreviation

RAPD, Random amplified polymorphic DNA; RFLP, restriction fragment length polymorphic; AFLP, amplified fragment length polymorphism;SSRs, simple sequence repeats; PCR, polymerase chain reaction.