All identical twins may share a common set of chemical markers on their DNA

Identical twins share many things, including DNA but new research suggest there is a signature of the twinhood. Part of the  epigenome, which are chemical markers that influence genes without altering sequence. These signatures could be used to identify a twin who might have lost their sibling in the womb or separated at birth. It is known that monozygotic twins form from the same zygote splitting into two embryos during development, but it is not clear why it happens is unclear. Scientists begin to look at the epigenetic differences along 450,000 sites of the genome of roughly around 6,000 monozygotic twins and dizygotic. 834 sites in identical twins were highly similar, from young to old twins, and from geographically different locations. These markers were very common among the twins that as of now, there is an 80% accuracy of identifying a twin who might have lost their sibling without even knowing that were a twin.