Extended Data Fig. 8: DSB maps on the PAR and autosomal mo-2 regions.

a, SSDS sequence coverage (data from previous reports^7,20) is shown for the X chromosome PAR (shown in a different form previously²⁰), the Y chromosome PAR and the mo-2-adjacent regions of chromosomes 9 and 13. The dashed segments indicate gaps in the mm10 genome assembly. We did not assess chromosome 4 because available assemblies are too incomplete. b, Regions adjacent to the mo-2 region on chromosome 9 show an SSDS signal that is reproducibly increased relative to the chromosome 9 average in wild-type testis samples but not in maps from Ankrd31^−/− testes or wild-type ovaries. Two of the SSDS browser tracks are reproduced from a. The bar chart shows enrichment values from individual SSDS maps (T1–T9 are maps from wild-type testes; O1 and O2 are from wild-type ovaries³¹). Enrichment values are defined as coverage across the indicated coordinates relative to the mean coverage for chromosome 9 (see Methods for details). Ovary sample O1 and the Ankrd31^−/− adult sample are known to have poorer signal-to-noise ratios than the other samples^20,31. For all SSDS coverage tracks, reads that map to multiple locations are included after random assignment to one of their mapped positions. However, the same conclusions are reached about ANKRD31 dependence and PRDM9 independence of the signal on chromosomes 9 and 13 if only uniquely mapped reads are used. c, Oocytes incur substantially fewer DSBs than spermatocytes near the mo-2 region on chromosome 9. The SSDS signal is from a previous study³¹ (samples T1 and O2). The X chromosome PAR is shown for comparison (previously shown to be essentially devoid of DSBs in ovary samples³¹). See b for quantification.