Double colour 5S and 28S rDNA FISH on <i>X</i>. <i>tropicalis</i> and <i>X</i>. <i>mellotropicalis</i> chromosomes.

<p>DAPI counter-stained metaphase spreads showed all (A) 20 chromosomes (B&W) in <i>X</i>. <i>tropicalis</i> and/or (D) 40 chromosomes in <i>X</i>. <i>mellotropicalis</i>. 28S rDNA amplicon labelled by Digoxigenin-11-dUTP (green) stained (B) XTR 7 secondary constriction and telomeres of XTR 6, 7 and 9 and/or (E) XME 7a secondary constriction and telomeres of XME 4a and 5b. 5S rDNA amplicon labelled by Biotin-16-dUTP (red) revealed positive signals on telomeric segments of (C) XTR 2, 3, 4, 5, 6, 7, 8 and 9 and/or (F) XME 4a, 5b and 8b. Arrows show NORs situated on secondary constrictions of (B) XTR 7 and (E) XME 7a. Scale bar represents 10 μm.