Figure 2

The number of meiotic DSBs is reduced in Gal4BD-Spo11 males. Chromosomal spreads from earlier (zygotene) and later (pachytene) stage spermatocytes were immunostained with antibodies to the DMC1 protein (red) to indicate the appearance and repair of DSBs in wild type mice and mice carrying one or two Gal4BD-Spo11 alleles. Chromosome cores were stained with antibodies to the axial element component SCP3 (green), and progression of homologous synapsis was monitored with antibodies to the component of the central element of the synaptonemal complex SCP1 (white).