How human eggs stay “fresh” for 50 years
A new study published in the journal Nature reveals how dormant human eggs remain viable in ovaries for decades. Genomics experts say that eggs essentially go into ‘standby mode’ by turning off an energy-generating cell pathway.
The chemical reactions in cells used to generate energy create harmful molecules called reactive oxygen species. As these accumulate, they can damage DNA, and in extreme cases, even cause cells to self-destruct.
By going into hibernation mode, the cells skip a fundamental metabolic reaction which also creates the biggest risk to the cell’s health, said Aida Rodriguez, one of the lead researchers of the study.
“Humans are born with all the supply of egg cells they have in life,” said Rodriguez.
“As humans are also the longest-lived terrestrial mammal, egg cells have to maintain pristine conditions while avoiding decades of wear-and-tear.”
Rodriguez and colleagues used a powerful suite of analytical tools including live cell imaging to dive deeper into this dormant state. They studied the eggs of an aquatic frog native to sub-Saharan Africa called Xenopus, as well as eggs from human donors.
The team watched as an enzyme known as complex I acts as a molecular switch that turns mitochondria on to generate energy. Complex I…
