Genes can reveal the time of death of crime victims

Genes may help pinpoint a crime victim’s time of death, scientists claim.  

Researchers recently looked at 9,000 samples from 36 different type of bodily tissue from donated cadavers.

For each sample, the scientists knew how long had passed between death and the preservation of the body.   

Researchers found that after death, different tissues responded in a wide variety of ways.

Some genes, for example, can continue to work for up to four days in a last-ditch attempt to save their cells – despite the death of the host. 

Some genes can continue to work for up to four days in a last-ditch attempt to save their cells - despite the death of the host. Researchers use levels of RNA to see better determine a cause of death (stock)

Some genes can continue to work for up to four days in a last-ditch attempt to save their cells - despite the death of the host. Researchers use levels of RNA to see better determine a cause of death (stock)

Some genes can continue to work for up to four days in a last-ditch attempt to save their cells – despite the death of the host. Researchers use levels of RNA to see better determine a cause of death (stock)

While the clearest readings come from the skin, thyroid, subcutaneous fat and lungs, the readings for the spleen and brain changed very little after death.

To find out how gene expression changed once a person had died, the research team compared blood samples ante-mortem (before death) and post-mortem (after death). 

By doing this, the researchers found a ‘cascade’ of genetic changes that fuel the death of cells in the body and the shutdown of the immune system.

These cascades involved a chemical called RNA, a molecule which is very similar to DNA, but does not form the famous double-helix structure.

RNA is heavily involved in turning our genetic code into usable materials, such as proteins. 

In order to gain an idea of activity decrease in the different tissues of the body after death, researchers looked at the levels of RNA.

They found the decrease in RNA levels was consistent and could be used to accurately trace back to the time of death.  

Although it isn’t ready to be used in the field yet, the levels of RNA were found to be consistent across several different corpses. 

Scientists believe they can use these readings to predict time of death to within an hour. 

However researchers, led by the Centre for Genomic Regulation in Barcelona, stress that their findings have not yet been proven to work beyond 24 hours after death. 

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