Figure EV1. Birth of mice following injection of oocytes with primary spermatocytes collected from germline‐specific Exoc1‐knockout mice.

1. Multinucleated cells (syncytial spermatocytes) obtained from an Exoc1‐knockout male mouse. Each multinucleated cell contained 2–4 spermatocyte nuclei. Differential interference contrast microscopy (left) and Hoechst‐staining (right) images. Bar = 10 μm.
2. Mice born from Exoc1‐knockout spermatocytes.
3. Polymerase chain reaction analysis in mice born from Exoc1‐knockout spermatocytes. Mice #2, #3, and #4 carried the Exoc1‐knockout allele (del) while mice #1, #5, and #6 did not. Three pups that did not carry the Exoc1 mutation were most likely derived from spermatogonia that escaped the Cre‐induced Exoc1 deletion. The expected amplicon sizes are as follows: flox allele, 1,426 bp; wild type allele, 1,291 bp; deletion allele, 490 bp.