Mitochondrial supplementation of Sus scrofa metaphase II oocytes alters DNA methylation and gene expression profiles of blastocysts.

Mitochondrial DNA (mtDNA) copy number in oocytes correlates with oocyte quality and fertilisation outcome. The introduction of additional copies of mtDNA through mitochondrial supplementation of mtDNA-deficient Sus scrofa oocytes resulted in (1) improved rates of fertilization, (2) increased mtDNA copy number in the 2-cell stage embryo and (3) improved development of the embryo to the blastocyst stage. However, it is still unknown if mitochondrial supplementation alters global and local DNA methylation patterns during early development. Therefore, we analysed gene expression and DNA methylation status in Sus scrofa blastocysts to assess the effect of mitochondrial supplementation.