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New Discovery - Identical Twins Don't Have Identical DNA

DNA Worldwide Group and their laboratory partners Eurofins Forensic are the first in the world to discover and prove that identical twins have differences in their genetic makeup. 

This not only changes the teaching that identical twins have the same DNA but it also means for the first time forensic and paternity testing can identify which identical twin was involved. This has all been possible thanks to a dedicated team that have successfully completed a research project to genetically discriminate “identical” monozygotic twins. Until this point it has been only theory that monozygotic twins are 100% genetically identical.

On a statistical level about 6 in 1,000 males are identical twins. However, until now DNA testing could not be used in criminal or paternity cases involving identical twins as you could not tell them apart. With cases involving identical twins hitting the world press on a regular basis covering cases from murder, child custody or inheritance it is a pressing issue. Even the best Forensic labs around the world accepted that analytical restrictions meant nothing further could be done, however, the team at the DNA Worldwide partner lab pushed the limit of DNA testing to great success.

To do this they took Forensic DNA profiling and Genomic Sequencing and combined them together. Technically, the scientists applied ultra-deep next generation sequencing and combined this with bioinformatics. Sequencing of DNA from sperm samples of two twins and from the blood sample of the child of one twin was conducted. The Bioinformatic analysis identified five differences (mutations), called Single Nucleotide Polymorphisms (SNPs) present in the twin father and the child, but not in the twin uncle. These SNPs differences were confirmed by what is known as Sanger sequencing.

Combining these results give experimental evidence for the hypothesis that rare mutations in the genes will occur early after or before the human blastocyst has split into two, at the origin of twins, and that such mutations will be carried on and are taken into life.

The DNA differences and methods that the DNA Worldwide laboratory used provide a solution to the complex paternity and forensic cases involving identical twins. DNA Worldwide Group and its partner are the first company to offer this testing. The peer-reviewed study “Finding the needle in the haystack: Differentiating “identical” twins in paternity testing and forensics by ultra-deep next generation sequencing” is available here.

David Nicholson, Managing Director, comments:

“It is a great achievement for Scientists at our lab to establish and prove that monozygotic (identical) twins are genetically not 100% identical. With our laboratory we are now the only company worldwide that can offer testing to courts, solicitors and authorities to identify the difference between identical twins”

The DNA Worldwide “Identical Twin Test” is available now.

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