Figure 5. Birth of spermatocyte‐derived offspring following embryo transfer.

1. Mouse pups born following spermatocyte injection (left) and the birth rates following embryo transfer (right). The numbers in the graph indicate: (number of pups born)/(number of embryos transferred). For detailed results, see also Appendix Table S2.
2. Histology of the testis of a Stx2^repro34 mouse. Arrowheads indicate multinucleated cells containing spermatocyte‐like nuclei. There are no spermatids or spermatozoa. Bar = 50 μm.
3. An MII oocyte injected with a putative spermatocyte nucleus from a multinucleated cell in a Stx2^repro34 mouse testis, showing the typical paired meiotic chromosomes. Bar = 20 μm.
4. A multinucleated cell isolated from a Stx2^repro34 mouse testis, showing four nuclei. Differential interference contrast (left) and Hoechst‐stained (right) images. Bar = 10 μm.
5. Left: mouse pups born following microinjection with putative primary spermatocyte nuclei isolated from multinucleated cells; Right: birth rate of pups following Stx2^repro34 spermatocyte microinjection.
6. Genomic sequencing confirming the origin of pups from Stx2^repro34 spermatocytes. Arrows indicate the expected point mutation of Stx2^repro34 . Y indicates a hybrid status with T and C bases.