Study proves identical twins not identical genetically

EBERSBERG, Germany, Dec. 10 (UPI) -- Scientists in Germany say they've made a breakthrough in genetic and forensic research by discovering genetic differences between identical twins.

Researchers at the genomics firm Eurofins Scientific say their work has confirmed that identical twins, also known as monozygotic twins, are not genetically identical and it is possible to genetically discriminate between them.

It had previously been believed DNA "fingerprinting" testing could not be used in crime or paternity cases involving identical twins, but the new research offers a way to solve forensic and paternity cases involving monozygotic twins as originators of DNA traces, a Eurofins Scientific release said Tuesday.

The researchers sequenced DNA from sperm samples of two twins and from a blood sample of the child of one of them. Analysis revealed five mutations, so-called Single Nucleotide Polymorphisms, present in the twin father and the child, but not in the twin uncle.

The results suggest rare mutations will occur shortly after or before the human blastocyst has split into two -- the origin of twins -- and that such mutations will be carried on into succeeding generations.

The study has been published in the journal Forensic Science International: Genetics.