DNA can be extracted from different tissues.
From hair samples, two different types of DNA can be extracted: mitochondrial DNA and nuclear DNA.
In criminal cases, hair samples can be tested using DNA analysis, which is the only scientific method to prove if they belong to a specific individual. Microscopic hair analysis cannot prove if a specific hair sample belongs to a person, due to its inefficiency to accurately compare different samples of hair and relate them to specific individuals. This method, used in a high number of criminal cases that eventually resulted in criminal sentences, was the one used in a case from 1985.
George Perrot was accused and subsequently sentenced to prison, based on a hair sample that was tested using microscopic analysis.
In the year 2013, the FBI admitted that this technique was not valid, and this admission caused major problems given that many cases were based -and eventually resulted in jail or death sentences- on microscopic analysis of hair samples.
In april 2015, the FBI, the National Association of Criminal Defense Lawyers, the Innocence Project and the US Justice department started an investigation aimed to discover the truth about the mistakes made by the widespread use of microscopic analysis of hair samples in criminal cases.
Answer:
DNA can be extracted from different tissues. From hair samples, two different types of DNA can be extracted: mitochondrial DNA and nuclear DNA. In criminal cases, hair samples can be tested using DNA analysis, which is the only scientific method to prove if they belong to a specific individual. Microscopic hair analysis cannot prove if a specific hair sample belongs to a person, due to its inefficiency to accurately compare different samples of hair and relate them to specific individuals. This method, used in a high number of criminal cases that eventually resulted in criminal sentences, was the one used in a case from 1985. George Perrot was accused and subsequently sentenced to prison, based on a hair sample that was tested using microscopic analysis. In the year 2013, the FBI admitted that this technique was not valid, and this admission caused major problems given that many cases were based -and eventually resulted in jail or death sentences- on microscopic analysis of hair samples. In April 2015, the FBI, the National Association of Criminal Defense Lawyers, the Innocence Project, and the US Justice Department started an investigation aimed to discover the truth about the mistakes made by the widespread use of microscopic analysis of hair samples in criminal cases.
