Figure 1

Main differences between murine, porcine, bovine and human oocyte size at maturation, time to maturation, early embryo development and embryonic genome activation (EGA). Color intensity of oocytes and embryos refers to lipid density. Mean size of oocytes at maturation are presented in proportion (mice ~80 μm). Average time periods of maturation and embryo development after onset of fertilization are illustrated by block arrows: oocyte maturation in hours (green arrows), transition from zygote to two-cells stage in hours (light purple arrows), transition of two-cells to blastocyst stage in days (purple arrows), and time to hatched blastocysts in days (dark purple arrows). Data were collected from in vivo and in vitro studies [34, 54–72].