Protein in hair can help confirm a person's identity

During the criminal investigation, the identity of the suspect will be easily detected if forensic experts find evidence of the DNA at the scene. After putting the DNA sample into a computer program, they will get the results. If you notice in criminal movies, this process only takes a few minutes, but in reality it is not so fast.

So far, DNA is still considered the most effective tool in determining forensic medicine. However, when it comes to hair samples of missing people or hair samples found at the crime scene, the sequence of proteins in them can yield more information than finding DNA.

In a study published in the September 7 issue of PLOS One, researchers at Lawrence Livemore National Laboratory in California (USA) presented a method for extracting genetic information from proteins. Found in hair is very reliable. Glendon Parker, a Livermore biologist, and lead author of the study, said: "Currently, forensic science is highly dependent on DNA. I find that analyzing proteins in hair can provide More useful information in special cases ".

So far, DNA is still considered the most effective tool in determining forensic medicine.

On September 7, researchers at Lawrence Livemore National Laboratory in California (USA) presented a method of extracting genetic information from proteins found in hair that is very reliable in determining Identify someone's identity

Analyze hair samples by observing under a microscope

Currently, the problem that forensic scientists face is that DNA is broken quite quickly when it is not located inside living cells. And as hair grows, cells make hair strands die because they are stretched and moved away from the supply of nutrients. DNA can only exist inside the hair if it is hidden in the mitochondria.

Because the very small number of mitochondrial DNA in hair is often not enough to identify, scientists have to analyze hair samples by observing under a microscope. They can look at the hair color and the specific physical properties of the hair to assess whether the hair sample from the crime scene is appropriate for the suspect. However, experts believe that this analysis only gives objective results.

George Sansabaugh, a professor of biomedical and a forensic medicine at the University of California, Berkeley, said: "Due to the difficulty of obtaining reliable information from hair morphology, and difficulty in extracting DNA from hair, so the forensics rarely turn hair into evidence for consideration. "

A better method of identifying identity

On the other hand, protein is more stable than DNA and it is also abundant in hair. Mutations in DNA are translated into proteins and sometimes, they can sometimes change the protein structure by exchanging an amino acid. Deon Anex, a chemist at Livermore, co-authored the study, said: "We are looking for such changes in protein structure and in that way we can deduce what's in the original DNA. In other words, even if the DNA loses or is decomposed by light, temperature or other environmental factors, benign changes in the protein found in the hair can be used to identify the name. count someone ".

Anex and his team analyzed hair samples from more than 76 people, both men and women, of European descent. In addition, they analyzed hair samples from 6 skeletons left over from the years 1700 and 1800. They found 185 different amino acid samples, so they could track the genetic identity of each individual. .

Even if DNA is lost or decomposed by light, temperature or other environmental factors, benign changes in proteins found in hair can be used to identify someone.

The research team also compared their protein identification method with DNA samples that were known from the blood of the test subjects and could correctly identify (98.3%) people with samples. That hair. And the possibility of protein analysis errors is only 1.98%.

From the study, the scientists identified that protein analysis provides a 1 / 100,000 distinguishing ability, meaning that only 1 individual in 100,000 people can share the same protein structure change. However, hair-derived mitochondrial DNA provides only one specific type in 1 / 10,000 people, which means that the new technology could be a big step in overcoming shortcomings in current forensic examination. now on.

The research team has begun to expand their research into analyzing proteins from other tissues such as bones, teeth and skin to provide more reliable evidence that it is possible to hope that a day away from proteins can be used. used to identify certain objects, like DNA.