Structure and organization of the B genome based on a linkage map in Brassica nigra

We constructed a genetic map on Brassica nigra based on a segregating population of 83 F₂ individuals. Three different types of molecular markers were used to build the map including isozymes, restriction fragment length polymorphisms (RFLP), and random amplified polymorphic DNA (RAPD). The final map contained 124 markers distributed in 11 linkage groups. The map covered a total distance of 677 cM with the markers distributed within a mean distance of 5.5cM. Of the sequences found in the B. nigra map, 40% were duplicated and organized into three different types of arrangements. They were either scattered throughout the genome, organized in tandem, or organized in blocks of duplicated loci conserved in more than 1 linkage group.