Fig. 1.

Design and results for the qualitative PCR markers. a Scheme for the primer design with emphasis on the B-specific and control fragments of scaffold_26. Three genomic sequences of different fishes: Dicentrarchus labrax, Dicentrarchus labrax and Oreochromis niloticus (FQ310507, FQ310506, and XM_003444758, respectively) were used to establish a consensus for comparison with the 454 sequencing data of the microdissected B chromosome (contig_182). b A 1 % agarose gel showing PCR products from B-positive (+) and B-negative DNA (−) samples. Note that the B- samples present only one DNA fragment (control fragment), whereas the B+ samples present two fragments (the control fragment and a B-specific fragment). c FISH using the PCR marker region sequence based on scaffold_26 as a probe. An arrow indicates the B chromosome, and the scale bar indicates 5 μm