Fig. 2.

Emergence of a Rec8-dependent grid of punctate interactions in meiosis. a Hi–C contact maps of chromosome 11 for the indicated genotypes at 2 kb resolution, showing near-diagonal interactions. Lower panels: log2(insulation); cis/total ratio, Rec8 ChIP-seq³⁰. Insulation and cis/total calculated from ndt80∆ maps. Green circles: positions of Rec8 sites. Genome-wide cis/total (Spearman’s R = 0.62, P < 1e-10) and insulation (R = −0.23, P < 1e-10, insulation window = 20 kb) profiles are correlated with Rec8 occupancy. Colour scale as in Fig. 2b. b Zoom-in of chromosome 11 (0–200 kb) for wt-4h, ndt80∆ and rec8∆. Contact probability versus genomic distance, P(s), for G1 (ndt80∆-0h) and ndt80∆ and rec8∆. Data are the average (n = 2) except for wt-4h. While faint locus-specific patterns exist in rec8∆, there is no global enrichment at Rec8 sites (see f and g). Rec8 peak sites called from ChIP-seq data³⁰ are indicated in green. Interactive view: http://higlass.pollard.gladstone.org/app/?config=Twrh61jGT4SlxotaguTIJg. Comparison to published ndt80Δ-arrested Hi-C data²⁰: http://higlass.pollard.gladstone.org/app/?config=NKoclcPJRTuah4ZrQPPm_Q. c Simplified illustration of how a grid of peaks on a Hi-C map can emerge between Rec8 sites either by transitive contacts between adjacent loops, or by loops that skip over adjacent sites. Experimentally observed grids extend much further than separation = 2 (Supplementary Fig. 4c). d Cis/total ratios for Rec8 (green) and nonRec8 (grey) sites for indicated datasets, showing an elevated cis/total frequency (0.85 versus 0.77) at Rec8 sites in ndt80∆. e Contact probability versus genomic distance, P(s), between Rec8-Rec8 sites (green), Rec8-nonRec8 sites (light green) and nonRec8-nonRec8 sites (grey). Note elevated pairwise contact frequency (~2-fold at 20 kb) at Rec8 sites in ndt80∆. f Log2 ratio of contact frequency between adjacent Rec8 sites (separation = 1) compared to average cis interactions. g Log2 ratio of contact frequency centred at Rec8 sites compared to average cis interactions, showing mild insulation at Rec8 sites in ndt80∆. These distinctions (d–g) are similar in wild-type pachytene (4 h) yet absent in G1 (ndt80∆-0h) or in rec8∆