LONDON, Ontario, March 28 (UPI) -- Just like snowflakes, no two people are alike even if they're identical twins, Canadian genetics researchers studying the roots of schizophrenia said.
Researchers at the University of Western Ontario have been working to determine the genetic sequencing of schizophrenia using identical twins.
Molecular geneticist Shiva Singh looked at about 1 million markers of identical twins (and their two parents) where only one twin had schizophrenia, a university release said Monday.
"We started with the belief that monozygotic (identical) twins are genetically identical, so if one member of identical twins has schizophrenia, then the risk for the other twin should be 100 percent, if it's all due to genes," Singh said. "However, studies over the years have shown that the risk of the disease in both twins is only 50 percent."
Singh and his colleagues have demonstrated that monozygotic twins are not genetically identical.
"So if schizophrenia is in the genes, then the difference in the genetic makeup of monozygotic twins, with only one disease twin, must have something to do with the disease," he said.
Singh found about 12 per cent of DNA can vary across individuals.
"Cells are dividing as we develop and differentiate," he said. "More importantly, these cells may lose or acquire additional DNA. The genome is not static."