Aging brings a buildup of genetic mutations in our cells, contributing to age-related diseases. However, a new study published in Science Advances uncovers an interesting exception: the mitochondrial DNA (mtDNA) of human egg cells in women appears unaffected by these age-related genetic changes.
Science AdvancesMitochondria serve as cellular energy powerhouses. Although most mtDNA mutations are harmless, some can lead to diseases like Leigh Syndrome in children, causing seizures and heart problems. The research, focused on immature egg cells called oocytes, sought to determine if their mtDNA mutations increase with age.
The study utilized DNA-sequencing techniques to identify mutations in 80 single oocytes from 22 women aged between 20 and 42, as well as analyzing mitochondrial DNA mutations in the same women's blood and saliva samples.
Results revealed that while mtDNA mutations increase in blood and saliva cells with age, they remain stable in egg cells. This suggests a specialized mechanism protecting eggs from genetic damage seen elsewhere in the body.
“mtDNA in human oocytes is protected against mutation accumulation with aging and has functional consequences,” stated the researchers. “These findings are particularly timely as humans often reproduce later in life.”
The few mutations detected mostly occurred in non-coding regions of mtDNA rather than in protein-production areas. Previous research suggested that older mothers might pass on more mitochondrial mutations, but this study challenges that idea.
Although the sample size was small and did not cover a woman's entire reproductive lifespan, these findings may offer valuable insights for reproductive counseling. Women opting to have children later in life may face fewer concerns about passing genetic mutations.
The article was written by Paul Arnold, edited by Gaby Clark, and fact-checked by Robert Egan—representing careful human journalism. We depend on readers like you to support independent science reporting.