Ex utero mouse embryogenesis from pre-gastrulation to late

Read the attached research paper and answer the following questions.

  1. What are some of the conditions that had to be maintained for the growth of ex utero embryos. 

2. What day were these embryos grown to (mice are on embryonic day 20 (E20)), were they normal to this point / how many development marks were analyzed to determine this? 

3. What is a factor that would have to be overcome to continue ex utero development? 

4. Summarize what the authors are showing in Figure 4 of the paper. 

5. The last sentence of the article notes that this work sets the stage for expanding ex utero embryo research to different mammalian species and from stem cell aggregated synthetic embryos. Should we study human embryos with this technique if they can be developed in culture from stem cells. Why or why not?