Identical twins aren’t perfect carbon copies of each other even at birth.
Twins emerge from the womb carrying different chemical marks on their DNA that influence the activity of individual genes, a new study shows. Known as epigenetic markers, these alterations don’t change the underlying genetic information. But by regulating the activity of certain genes, they can profoundly influence how the DNA blueprint is used to create and operate a living organism.
Past research has shown that identical twins bear some differences in epigenetic markers. But those differences were thought to arise after birth, as twins have different life experiences and encounter different environments.
The new study — the first to measure epigenetic profiles in newborns — suggests that subtle differences in conditions within the womb can leave marks on fetal DNA that may have long-term consequences for adult health.
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