A study published in Nature Genetics reports that mice can inherit patterns of gene regulation across multiple generations without any alteration to the DNA sequence itself. The research team, led by scientists at the European Molecular Biology Laboratory in Rome, tracked epigenetic marks — chemical modifications to DNA and its associated proteins that control gene activity — across several generations of inbred mouse lines.
The investigators found that specific epigenetic states at thousands of genomic locations were transmitted from parents to offspring at rates far exceeding random chance. These inherited marks influenced gene expression levels in the offspring, producing measurable phenotypic differences despite the animals sharing nearly identical DNA sequences.
The study focused on DNA methylation and histone modifications, two major epigenetic mechanisms. Using whole-genome bisulfite sequencing and chromatin immunoprecipitation, the researchers mapped these marks in sperm, oocytes, and early embryos to trace their transmission through the germline.
Statistical analysis showed that a significant fraction of the variation in gene expression among the mice could be attributed to these inherited epigenetic states rather than to genetic variants. The authors estimate that standard genome-wide association studies, which scan for DNA sequence changes linked to traits, would fail to detect this component of heritability.
The findings were replicated in independent cohorts and across different mouse strains, strengthening the case that non-Mendelian epigenetic inheritance is a widespread phenomenon in mammals. However, the researchers caution that the stability of these marks over many generations and their relevance in natural populations remain open questions.
Experts not involved in the work note that while epigenetic inheritance has been documented in plants and invertebrates, evidence in mammals has been limited and controversial. This study provides the most comprehensive genome-wide evidence to date in a mammalian model system.
The research does not address human health directly, and the extent to which similar mechanisms operate in people is unknown. The authors emphasize that environmental factors capable of inducing such heritable epigenetic changes have not been identified in this experimental setting.
Future work will aim to determine how long these epigenetic states persist without selection, whether they respond to environmental cues, and how they interact with traditional genetic variation to shape complex traits.
If DNA is the instruction manual, we just opened a big second volume
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