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Identical twins' DNA separated in scientific first

Twin births have almost doubled in developed countries in four decades

The last hurdle in the domain of DNA profiling was cleared when scientists differentiated between the genetic profiles of identical twins at the University of Huddersfield in the UK.

Identical twins present the same DNA profile, which has led forensic scientists to dead ends in analyzing crime scene evidence.

Gene mutations that occur due to lifestyle differences -- for example if one twin smokes and the other doesn't, or if one works outside and the other works a desk-job -- can help discern one from the other, but this method is well known to be expensive.

Melting the DNA, however, is less costly and differing temperatures at which the twins' separate DNA strands melt marks the distinction between siblings, the researchers found out.

It's called the "high resolution melt curve analysis" (HRMA), developed by Dr. Graham Williams and his Forensic Genetics Research Group at U of H.

"What HRMA does is to subject the DNA to increasingly high temperatures until the hydrogen bonds break, known as the melting temperature," says Dr. Williams. "The more hydrogen bonds that are present in the DNA, the higher the temperature required to melt them."

Young twins and adult twins who lead similar lifestyles could be indistinguishable even with HRMA, says Dr. Williams, who acknowledges that the method requires high-quantity samples that might not be available on the scene of a crime.

"Nevertheless, we have demonstrated substantial progress towards a relatively cheap and quick test for differentiating between identical twins in forensic case work," says Dr Williams.

A paper on the project was published in the journal Analytical Biochemistry.