News | Human Eggs May Have Built-In Genetic Protection Against Aging
A genetic study of human eggs challenges the assumption that older eggs inevitably accumulate more mutations. New mitochondrial DNA mutations did not clearly increase with women’s age, suggesting that human eggs may have evolved protection that preserves genetic stability for decades. The findings were published in Science Advances.
“We usually think age-related mutations accumulate so older people have more,” said Kateryna Makova of Pennsylvania State University. “But expectations are not necessarily facts.”
Mitochondria supply energy to nearly all cells and are inherited only from the mother. Most mitochondrial DNA mutations cause no problems, but some cause disease, especially in energy-intensive muscles and the nervous system. Ruth Lehmann of MIT, who was not involved, noted that oocytes serve as energy reservoirs.
Older mothers are more likely to transmit chromosomal abnormalities, so scientists expected a similar trend in mitochondrial DNA. Makova’s team used high-precision sequencing to examine 80 eggs from 22 women aged 20–42 for new mitochondrial mutations.
Mutation numbers did not rise with age in eggs, unlike saliva and blood cells from the same women. Makova said humans may have evolved mechanisms that reduce the mutational burden in eggs and support reproduction at later ages.
Earlier work in rhesus macaques offered a clue: mitochondrial mutations in eggs increased until peak reproductive age, about 9 years, then stabilized. Barbara Arbeithuber of Johannes Kepler University in Austria said studies of younger humans might reveal a similar pattern.
Despite the small sample, the study offers a new direction for understanding how eggs remain genetically stable over time and may influence research on female reproductive aging.
News | Human Eggs May Have Built-In Genetic Protection Against Aging
News | Human Eggs May Have Built-In Genetic Protection Against Aging
A genetic study of human eggs challenges the assumption that older eggs inevitably accumulate more mutations. New mitochondrial DNA mutations did not clearly increase with women’s age, suggesting that human eggs may have evolved protection that preserves genetic stability for decades. The findings were published in Science Advances.
“We usually think age-related mutations accumulate so older people have more,” said Kateryna Makova of Pennsylvania State University. “But expectations are not necessarily facts.”
Mitochondria supply energy to nearly all cells and are inherited only from the mother. Most mitochondrial DNA mutations cause no problems, but some cause disease, especially in energy-intensive muscles and the nervous system. Ruth Lehmann of MIT, who was not involved, noted that oocytes serve as energy reservoirs.
Older mothers are more likely to transmit chromosomal abnormalities, so scientists expected a similar trend in mitochondrial DNA. Makova’s team used high-precision sequencing to examine 80 eggs from 22 women aged 20–42 for new mitochondrial mutations.
Mutation numbers did not rise with age in eggs, unlike saliva and blood cells from the same women. Makova said humans may have evolved mechanisms that reduce the mutational burden in eggs and support reproduction at later ages.
Earlier work in rhesus macaques offered a clue: mitochondrial mutations in eggs increased until peak reproductive age, about 9 years, then stabilized. Barbara Arbeithuber of Johannes Kepler University in Austria said studies of younger humans might reveal a similar pattern.
Despite the small sample, the study offers a new direction for understanding how eggs remain genetically stable over time and may influence research on female reproductive aging.
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