Fig. 1: Complete assembly of ROBs.
From: The formation and propagation of human Robertsonian chromosomes
a, Working model for the dependence of ROB formation on recombination between SST1 repeats (pink triangles) located in PHRs (coloured bands) on the short arms of human chromosomes 13, 14 and 21. The adjacent 45S rDNA arrays facilitate 3D proximity by co-locating in nucleoli. b, Schematic representation of the main SST1 arrays and flanking sequences in acrocentric chromosomes from the CHM13 genome. This region is similar on chromosomes 13 and 21 and is inverted on chromosome 14. c–e, Representative images of ROBs from GM03786 (c), GM04890 (d) and GM03417 (e) cell lines. Left image, chromosome labelled with an SST1 probe (magenta) and whole chromosome paints as indicated. Centre image, chromosome labelled with an SST1 probe (magenta) and centromeric satellite probes for cen14/22 (orange) and cen13/21 (green). DNA was counterstained with DAPI. Right image, magnified view showing SST1 localization between the two centromere arrays. Scale bar, 1 µm. Right, averaged intensity profiles of lines drawn through the centromeres of multiple ROBs (GM03786: n = 10, GM04890: n = 20, GM03417: n = 11). Intensity profiles were aligned to the peak of the Gaussian of the SST1 signal and normalized to the maximum intensity of each channel. Error bars denote s.d. Bottom, synteny plots comparing the assembled ROB to the CHM13 genome sequence. The structure of each fused region is shown in detail. a.u., arbitrary units.
