Figure 5.

The effects of O₂ tension and genetic background on growth rates in vitro. The effect of 5% or 20% O₂ on the proportion of (A) hybrid strain and (B) B6 mouse zygotes cultured as groups of 10 in 10 μL sIVF media achieving developmental landmarks at 48, 72, 96 and 116 h post-hCG. (C) the total number of cells in the resultant blastocysts, and (D) the number of these cells with fragmented nuclei in the resultant blastocyst 116 h post-hCG were assessed. At least 200 hybrid strain and 130 B6 embryos from 4 independent replicates were tested. *p < 0.01, compared to the embryos achieving the same landmarks in 20% O₂ condition.