Linkage Map Construction for Silkworm (Bombyx mori L.) Based on Amplified Fragment Length Polymorphism Markers

The domesticated silkworm, Bombyx mori, is of high commercial importance as a silk producer and is also widely used for implementation of basic and applied research. It is important to understand its genome organization using molecular markers for genetic studies and for breeding purposes. In this study, a genetic linkage map using 204 amplified fragment length polymorphism (AFLP) markers was developed. Twenty PstI/TaqI primer combinations were used to genotype 78 progenies from an F2 population of the P107×Khorasan Lemon cross. Each primer combination generated an average of 10.2 AFLP markers qualified for linkage mapping. All the 204 AFLP markers were assigned to 12 linkage groups at the Logarithm of Odds (LOD) threshold of 2. The number of markers in the linkage groups ranged from 2 to 53. There were seven major linkage groups with 13-53 markers and five small linkage groups with 2-6 markers. The 12 linkage groups varied in length from 12.3 to 938.4 cM and the total length of linkage map was 4262 cM, giving an average marker resolution of 20.89 cM. This study presents the preliminary step for further marker-assisted research on silkworm, including Quantitative Trait Loci (QTL) and introgression analyses.