Identical twins share a level of molecular similarity that influences their biological characteristics, an international group of researchers has discovered in a recent study which was published in the journal Genome Biology.
Proposing a mechanism to explain the unusually high level of similarity, researchers show that it is associated with risk of cancer in adulthood, according to the study.
By analysing data from a genome-scale study of DNA methylation in monozygotic and dizygotic twins, researchers identified genomic regions at which the epigenetic similarity of monozygotic, or identical, twins are substantially greater than can be explained by their genetic identity.
The characteristics of an individual depend on epigenetics, which refers to molecular mechanisms that determine which genes will be turned on or off in different cell types, as well as genes inherited from the parents, explains senior author in the study, Robert A. Waterland.
“Epigenetic super-similarity” results from the specific establishment of epigenotype – genetic patterns that compose DNA – prior to embryo formation during twinning.
Study findings establish a link between early embryonic epigenetic development and adult disease. Also, epigenetic super-similarity is a previously unrecognised phenomenon that may contribute to the phenotypic similarity of monozygotic twins, according to the study.