Genetics: Epigenetic signature specific to identical twins identified

Identical twins have a specific epigenetic signature in their DNA that persists from conception to adulthood, suggests a paper published in Nature Communications. The finding provides insights into the biology surrounding identical twin conception.

It is estimated that 12％ of all pregnancies may start as multiple pregnancies, but only 2％ are carried to term. This condition is known as vanishing twin syndrome. Understanding why identical twins arise has remained a mystery and as identical twins rarely run in families, the prevailing hypothesis has been that this phenomenon occurs at random.

Jenny van Dongen, Dorret Boomsma and colleagues studied several large international twin cohorts, to identify epigenetic signatures that are specific to identical twins. They found an epigenetic signature that is common across all identical twins, and persists from conception to adulthood. The authors also demonstrate that using this epigenetic signature allows them to identify if an individual was conceived as an identical twin, even if they are not known to be a twin.

Whether this epigenetic signature has any biological consequences for identical twins is not known and further studies are needed.