Figure 4.

BAC-FISH and linkage mapping of the Z chromosome in B. betularia. Meiotic chromosomes from males were counterstained with DAPI (light blue). The BAC probes were labeled with Cy3-dUTP, Green-dUTP and with a combination of both Cy3-dUTP and Green-dUTP, respectively. Hybridization signals indicate the physical positions of the 10 loci: laminin A (orange), kettin (violet), ABCF2 (red), tan (green), idgf (yellowish to orange), Paramyosin (red and green), period (yellow), 6-PGD (violet), Ldh (red) and Henna (green). (a) Pachytene spermatocyte complement with the ZZ bivalent identified by hybridization signals of 10 Z-linked gene-containing BAC probes. Scale bar=10 μm. (b) Chromosomal localization and synteny of 10 Z-linked loci between B. betularia and B. mori Z chromosomes. The recombinational positions of genes mapped to B. betularia linkage group 1 (LG1; left-hand vertical bar) are related to their physical positions in the BAC-FISH-painted Z chromosome of B. betularia (middle image) and in a scheme of the B. mori Z chromosome (right-hand vertical bar) by interconnecting lines; white lines indicate preserved gene order and yellow lines rearranged gene order between the two species.