The short answer is yes, but probably not in the way that you originally thought.
Using Short Tandem Repeats to profile suspects is one of the best ways to identify a suspect at the scene of a crime.
Everyone's DNA is very similar and the majority of a persons DNA is the same from person to person. It is these matching repeating pairs that make us human and distinguish us from other species. Its the few non-matching pairs that distinguish us from one another.
Identical twins don't follow these same rules and share almost all of the varying parts of their DNA that would normally be used to identify them from someone else.
The need to tell identical twins apart is not usually that big of a need, but in criminal conviction cases, especially those of a more violent nature they become very import to investigators.
Identical twins make up 0.3% of the population. Three in every thousand doesn't seem like a lot of people, but considering there are over 7.5 billion people on the planet today, that is a big number. How likely is it that just one of those people gets caught up in a violent crime?
So normal methods of DNA sequencing and identification in a criminal case involving identical twins don't work then what will?
Well it is true that everyone even twins have variations in their DNA. Somewhere in the millions of base pairs there are some differences. These differences usually occur in early development in the form of DNA mutations. Everyone has mutations in their DNA, most don't affect us, but they can come in handy when identifying differences in DNA among twins.
Although this is great news, we can identify differences in identical twins, the level of sequencing required for this kind of task is not practical. It can cost hundreds of thousands of dollars and takes months to complete. Few cases warrant this level of investigation, but there might be a simpler method identified by the Forensic Biology Group from the University of Huddersfield, UK.
Researchers at the University of Huddersfield studying methylation identified that "if the sequences are different, then in theory the melting temperature should be different" and thus can vary between individuals. Simply put, different DNA will melt at different temperatures and this minute difference in melting point can be used to distinguish different DNA. If you want to read an article about the teams findings you can find it here: https://www.sciencedirect.com/science/article/pii/S0003269715000500
The team collected samples from 5 sets of twins and studied the melting temperatures of specific target zones in the DNA of each twin. Findings concluded that the theory was accurate and there are variations between the melting points of identical twins DNA.
This new discovery could potentially be used in many criminal cases involving twins to identify and place one at the scene of a crime.
Although sequencing DNA and looking for the little differences in base pairs is the most effective way to analyze someone's DNA it is just too expensive for every case. This new method of analyzing melting points could prove to be a cost effective way to identify criminals at the scene of a crime.