All of us share some portion of our DNA with our relatives and ancestors. This is part of why genetic material that comes from a family member can be used to help confirm the identity of someone who is deceased. This week, DNA was used in order to confirm that Osama bin Laden had been killed.
One of the biggest news events of the past week was the announcement that U.S. Forces had killed Osama bin Laden somewhere in Pakistan. The body was first identified through photographs. Later, a DNA sample was taken, and tested. This led John Brennan, assistant to the president for homeland security to conclude with 99.9% confidence that the body in question was, in fact, the body of Osama bin Laden.
Some people have wondered why they could not make that identification with 100% accuracy. The answer lies in how DNA is tested. Obviously, the first thing required is a sample of the DNA from the person in question. A test called a modern-day rapid DNA test is used in order to look at short sections that repeat themselves in the DNA sample. These tests are said to be incredibly accurate.
In addition to a family name, and a physical resemblance, we also inherit mitochondrial DNA and genetic mutations from those who came before us in our family tree. Therefore, two people who are very closely genetically related, will share more repeated patterns than people who have no relation to each other.
Scientists have, in the past, used samples of genetic material that came from a deceased person for the purpose of identification of the body. Cemeteries that are extremely old may no longer have existing records that clearly state who is buried in each plot. DNA can be used to figure out if a person’s ancestor is actually buried where he or she was said to have been. The DNA sample from the deceased ancestor can be compared with the DNA of a living descendant.
Paternity tests also require a genetic sample from both the child and the suspected father, in order to either prove, or rule out, a biological relationship between the two. This is another example of how a DNA sample can be used to determine, or to rule out, a biological familial relationship between two people.
Ideally, a genetic sample from a close relative of bin Laden would have been used in order to make a comparison. However, he did not have any full siblings. Instead, a sample of his DNA was compared with the DNA of his half sister.
It has been said that her DNA was obtained when she died in a hospital in Massachusetts. After comparing the samples, scientists were able to conclude that it was 1000 times more likely that the DNA that came from the body in question came from a sibling of the woman who was Osama bin Laden’s half sister, than it would be to have come from someone who was not biologically related to her. This type of phrasing is similar to how the results of paternity tests are phrased.
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