Fig. 1

Needles preparation for each embryonic day stage. A Puller. B needle used at ED3 (HH19) and ED4 (HH24). C needle used at ED5 (HH27). D needle used at ED6 (HH29) and ED7 (HH31). E needle used at ED8 (HH34) and ED9 (HH35). F needle used at ED10 (HH36)