Taking the ‘identical’ out of ‘identical twins’
Can you tell identical twins apart, genetically speaking? ?
Identical twins are a lot more common than you might think – they represent one in 250 people worldwide. Amid abandoned legal cases, high-profile acquittals of serious crimes and paternity suit dismissals, scientists were increasingly questioning the dogma that identical twins could not be genetically differentiated.
Only theoretical approaches existed to solve this conundrum, until a breakthrough by Eurofins companies busted the identical twin myth and provided an answer to the puzzle of how to tell identical twins apart.
Learn more in this interview with Burkhard Rolf , Managing Director of Eurofins Medigenomix Forensik GmbH.
Q: Why was it so important to be able to tell identical twins apart at a genetic level??
“You have to consider the implications outside of the scientific field. Previously, if two individuals shared the exact same DNA, there was no way to tell them apart from a legal perspective – which means if your suspect in a criminal case had an identical twin, you simply couldn’t prosecute them.”
“Finding a way to differentiate identical twins was a huge step towards bringing closure to families impacted by such cases.”
Q: How was the twin differentiation method developed?
“Eurofins Medigenomix Forensik and Eurofins Genomics in Germany, together the largest commercial DNA and genomic service provider in Europe, joined forces to develop the twin differentiation method.”
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“Together, we used next-generation sequencing to screen whole genomes for even the tiniest of differences.”
“Eventually, we found what we were looking for: rare mutations that occur very early in the embryonic stage and are therefore unique to each twin.”
“We were able to provide evidence that, because these changes happen so early in the embryo’s development, they can be found throughout the individual’s DNA, notably in their reproductive cells (gametes), meaning DNA samples from one identical twin can be distinguished from the other.”
“The genetic characteristic is inherited by their children, so it can also solve paternity cases involving monozygotic (‘identical’) twins as potential fathers.”
Q: To what extent has the method been utilised?
“Our method has been used to successfully establish paternity in a number of cases brought to us by family or criminal courts.”
“The first application of the test in a criminal case context was to support the Boston Police Department and Suffolk County District Attorney’s Office in a serial rape case, in which one of the offenders had an identical twin. We used saliva samples to unambiguously match the DNA to one twin, which was powerful evidence.”
“The feedback from the forensics community on our twin differentiation method has been overwhelmingly positive, we’ve certainly been kept busy with cases since its development, and are delighted to support the legal community!”