Related Experiment Video
Updated: Jun 6, 2025

Measuring Single-Cell Mitochondrial DNA Copy Number and Heteroplasmy Using Digital Droplet Polymerase Chain Reaction
Published on: July 12, 2022
The mitochondrial DNA copy number and ovary-related reproductive disorders: A bidirectional two-sample Mendelian
Ke Peng1,2,3, Xiao Han2,3, Congquan Wu2,3
1Department of Gynecology, The International Peace Maternity and Child Health Hospital, School of Medicine, Shanghai Jiao Tong University & Shanghai Key Laboratory of Embryo Original Diseases, Shanghai, China.
Objective:
In the present study, a bidirectional two-sample Mendelian randomization approach was utilized to explore potential causal relationships between mitochondrial DNA copy number (mtDNA-CN) and ovary-related reproductive disorders (ORRDs), including ovarian dysfunction, ovarian cyst, polycystic ovary syndrome (PCOS), premature ovarian failure (POF) and ovarian endometriosis.
Methods:
Genetic associations with mtDNA-CN were obtained from three genome-wide association study (GWAS) summary statistics from the UK Biobank, and ORRD data were investigated using summary statistics from the FinnGen cohort. Single nucleotide polymorphisms (SNPs) correlated with mtDNA-CN were selected as genetic instrumental variables (IVs) to estimate the causal effect of mtDNA-CN on ORRDs using the inverse-variance weighted (IVW) method with heterogeneity and pleiotropy analysis, and we repeated this in the opposite direction using instruments for ORRDs.
Results:
We found that the genetically predicted mtDNA was indicative of increased levels of PCOS (OR = 1.16; P < 0.001) and ovarian endometriosis (OR = 1.25; P = 0.007) in the IVW analysis and was not associated with the risk of other ORRDs. In the reverse direction, genetically predicted ORRDs were not associated with mtDNA-CN levels in the IVW analysis. Sensitivity and replication analyses showed the results to be stable.
Conclusion:
We found that mtDNA-CN may increase the risk of PCOS and ovarian endometriosis. This may have implications for mtDNA-CN as a biomarker for these conditions in clinical practice.
Related Concept Videos
Animal Mitochondrial Genetics
Nondisjunction
Non-nuclear Inheritance
Meiosis I
Prophase I is the most extended and complex step of meiosis I characterized by synapsis, chromosome pairing, and recombination of the homologous chromosomes. This process is facilitated by a proteinaceous structure called the...
Comparing Copy Number Variations and SNPs
Copy number variations or CNVs are the structural variations that cover more than 1kb of DNA sequence. The single nucleotide polymorphism (SNP), on the other hand, is a single nucleotide change or a point mutation that is found in more than 1%...
Oogenesis

