Forensic DNA testing with rootless hair

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Forensic DNA Testing

Hairs are the most common evidence that detectives can find on any crime scene. Unfortunately, only fragments of hair are available at the crime scene. And until now scientists were only able to extract DNA from hairs that had their roots attached. This leaves the detectives and scientists with very little evidence for forensic DNA testing.

Recently though researchers had a breakthrough and were able to extract DNA from rootless hair. Dr. Ed Green made this possible by using the technique, first used to extract DNA from fossilized bones. The fact that his DNA from rootless hair 100% matches the DNA obtained by saliva is what makes this technique more reliable.

Forensic DNA Testing

How does it work?

Due to the structure of hairs, everyone thought it doer doesn’t contain DNA but it was recently found that even hair contains nuclear DNA. Nuclear DNA is present in every nucleated cell from saliva to bones. This means it is also possible to extract DNA from rootless hairs.

Scientists use PCR to get the DNA sample found at the crime scene. In PCR a small fragment of DNA multiplies many times which in turn creates more than a billion copies of the same DNA sample. The final DNA profile helps to catch the criminal. It’s done by comparing this DNA profile with the DNA profiles of the suspects to determine the criminal.

Mitochondrial DNA Testing with hair samples.

Although mtDNA cannot help to identify a specific person it can help to differentiate between species. Since not every hair sample belongs to a human a way to differentiate between the species is helpful. It cannot help to identify a specific person due to its commonality in maternal lineage. This means the DNA could belong to the mother, daughter, or grandmother.


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