Science

Genetic differences between "identical" twins discovered

A new test is able to genetically discriminate between "identical" twins (Photo: Shutterstock)
A new test is able to genetically discriminate between "identical" twins (Photo: Shutterstock)
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A new test is able to genetically discriminate between "identical" twins (Photo: Shutterstock)
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A new test is able to genetically discriminate between "identical" twins (Photo: Shutterstock)

Although they only account for around three in every thousand deliveries, monozygotic, or "identical" twins are fertile fodder for crime writers and cop shows. This isn't surprising considering that DNA fingerprint testing is not able to genetically differentiate between the good and evil twin. But now German-based company Eurofins MWG Operon says it has found a way to do just that.

Scientists from Eurofins, a genomic services company specializing in forensics and paternity testing, sequenced DNA from sperm samples provided by two identical twins and a blood sample of the child of one twin. They found five mutations, known as Single Nucleotide Polymorphisms (SNPs), in the child and the father, but not in the twin uncle. This finding was confirmed using Sanger sequencing.

The scientists say this provides experimental evidence for the hypothesis that rare mutations will occur early after or before the twins originate with the splitting of the human blastocyst in two, and that these mutations will be carried on into somatic tissue and the germ line.

Eurofins, which is the first company to offer such a test, says it should prove useful in forensic and paternity cases involving monozygotic twins.

The team's study appears in the journal Forensic Science International: Genetics.

Source: Eurofins

5 comments
Slowburn
How many twins did they test?
Mack McDowell
Slowburn it sounds like they just tested 1 pair of twins It shows that their hypothesis has merit though and they need to perform further experiments to confirm it
Slowburn
@ Mack McDowell That was the point. At this point they have a plausible theory but it needs more research.
Bob
It's interesting how much is touted as certain about DNA testing when so much is yet unknown. It will be interesting to see what the next few years will bring. When many more full DNA analyses become available, I suspect we will all be more individual than currently thought.
AntonSeman
Very true. Result from just a pair of twins means nothing, inconclusive. However, I still don't get it. If both father and uncle has identical dna make up, of course the 5 mutations defenitely originate from the mother. By identifying the man married to the mother than we know who the father is. But if the mum also cannot tell which is which,or the good brother trying to protect the evil brother by claiming he is the father, what can they do. You can't simply have 5 diffrent mutations 'between' father and son only, as the father and uncle are identical. Their report should also say they also found 5mutations to their uncle too or else fewer mutation/more mutations should be expected to arrive at the conclusion that they can identify the father of the child. May be they should devise an experiment where both twins were sleeping with the same lady and have one offspring from each twin. By comparing the dna of the kids and mother 'may be' they can find conclusive evidence who is the father from each offspring.