SSR based linkage and mapping analysis of C, a yellow cocoon gene in the silkworm, Bombyx mori

• Published in: Insect science Vol. 15; no. 5; pp. 399 - 404
• Main Authors: Zhao, Yun-Po, Li, Mu-Wang, Xu, An-Ying, Hou, Cheng-Xiang, Li, Ming-Hui, Guo, Qiu-Hong, Huang, Yong-Ping, Guo, Xi-Jie
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.10.2008
• Subjects: Bombyx mori; C gene; carotenoid uptake; linkage map; SSR markers
• ISSN: 1672-9609; 1744-7917
• DOI: 10.1111/j.1744-7917.2008.00226.x

The yellow color of the cocoon of the silkworm Bombyx mori is controlled by three genes, Y (Yellow haemolymph), I (Yellow inhibitor) and C (Outer‐layer yellow cocoon), which are located on linkage groups 2, 9 and 12, respectively. Taking advantage of a lack of crossing over in females, reciprocal backcrossed F1 (BC1) progeny were used for linkage analysis and mapping of the C gene using silkworm strains C108 and KY, which spin white and yellow cocoons, respectively. DNA was extracted from individual pupae and analyzed for simple sequence repeat (SSR) markers. The C gene was found to be linked to seven SSR markers. All the yellow cocoon individuals from a female heterozygous backcross (BC1 F) showed a heterozygous profile for SSR markers on linkage group 12, whereas individuals with light yellow cocoons showed the homozygous profile of the strain C108. Using a reciprocal heterozygous male backcross (BC1 M), we constructed a linkage map of 36.4 cM with the C gene located at the distal end, and the closest SSR marker at a distance of 13.9 cM.