Fig. 6: DMC1 is recruited at meiotic DSB hotspots in Firrm cKO spermatocytes.

Percentages of on-axis RPA2 foci colocalized with on-axis DMC1 foci (a), and vice-versa (b) in spreads from mid-late leptotene to mid-zygotene/zygotene-like spermatocyte nuclei from 12-dpp control (gray), Firrm cKO (red) and Fignl1 cKO (orange) mice. n = 2 mice per genotype. c Numbers of and shared hotspots identified by DMC1-SSDS in spermatocytes from 12 dpp control and Firrm cKO mice. d DMC1-SSDS signal correlation between control and Firrm cKO mice at hotspots identified in both genotypes. The Spearman rho and associated p-value (two-sided) are shown. Red and green dots indicate hotspots that were significantly over- and under-represented in Firrm cKO compared with control spermatocytes (DESeq2, p-value < 0.1, log2FC > 0 and log2FC < 0, respectively). Unchanged autosomal hotspots are represented in gray and chromosome X hotspots by black circled diamonds. e Average plots (top) and corresponding heatmaps (bottom) of DMC1-SSDS intensity (fragments per million, FPM) in control (left) and Firrm cKO mice (right) for hotspots that overlap with SPO11-oligo hotspots⁷⁷ detected in both genotypes (common peaks), in control only (control-specific), or in Firrm cKO only (Firrm cKO-specific)(see Supplementary Fig. 7a–c). The center of intervals is defined as the center of SPO11-oligo peaks detected in B6 mice, as defined in ref. ⁷⁷. f Normalized average distribution of ssDNA type 1 fragments (see Methods) originating from forward (fwd) and reverse strands (rev) at common peaks, defined in (e), for control (dark red, orange) and Firrm cKO (dark blue, light blue). The SSDS signal was normalized to have the same cumulated amount of normalized average signal over common peaks (on a 5-kb window) for both genotypes. Source data are provided as a Source Data file.