Figure 1

Physical mapping of seven of the short satDNAs found in Locusta migratoria, showing the three patterns of chromosome distribution observed: non-clustered (a), clustered (d–g) and mixed (b,c). (a–c) show haploid mitotic metaphase cells from haplo-diploid embryos, whereas (d–g) show diploid cells from normal embryos. Each cell is shown in red color for satDNA FISH (upper panel) and merged with DAPI (lower panel). In (e,f) double FISH was performed to distinguish whether the sat-carrying chromosome was L2 instead of L1 (e) and whether S9 carried LmiS at04–18 in addition to rDNA (shown in green color) (f). Inset in (f) shows the S9 chromosome stained with DAPI, on the left and submitted to double FISH for LmiSat04–18 (red) and rDNA (green), on the right, which was selected from another cell showing lower chromosome condensation. Note the presence of three about similar sized satDNA blocks located in interstitial and distal regions of the S9 chromosome. In (g) note that LmiSat07–5-tel shows the typical pattern of telomeric repeats.