Abstract: Mitochondria，as an important organelle in eukaryotic cells with its own genetic material mitochondrial DNA(mtDNA) independent of the nuclear genome, provides the energy for cell activities. Due to its specific structural characteristics and unique biological environment, mtDNA has significantly higher mutation rate than nuclear genome. Mitochondria are the most numerous organelles in oocytes. The copy number variation and accumulation of structural mutations of mtDNA can result in the reduction of intracellular ATP synthesis, leading to adverse outcomes for the development of oocytes, early embryos and pregnancy. Morphological and genetic examination of chromosomes can reduce the rate of abnormal embryo transplantation. However, even if the embryos are intact, some embryo implantations are still failed. Therefore, further elucidating the relationship between mtDNA and embryo quality is of great significance for improving embryo quality and pregnancy outcome. The recently published literatures about the correlation between mtDNA variation and oocyte or embryo quality, and the interventions to improve oocyte quality, have been reviewed in this paper.

Key words: Mitochondria；, DNA, mitochondrial；, DNA copy number variations；, Mutation；, Oocytes；, Embryonic development