When we die it may be assumed that all bodily activity and functioning comes to a halt. However, new research has found that some of our cells may continue to function after death, and may even be more active!
When a gene is switched on, a RNA transcript is formed. RNA is the blueprints for the formation of proteins in the body and by analysing these transcripts, scientists can get an indication of what a cell, tissue or organ is doing (in disease and in health). This process is called transcriptomics.
However, obtaining the samples can be very difficult. Blood samples are easy to obtain, however gaining a sample from a living persons heart and liver can be more of a challenge.
As a result, researchers often rely on post mortem samples (tissues and organs which are removed from the body after death). However, it is not clear as to whether these samples give a true representation of bodily activity when the person is alive. For instance, samples are not taken immediately after death, they are normally obtained once the body has undergone post mortem examinations. Also, body decay may also affect the interpretations of transcriptomic data.
In the study published in Nature Communications , researchers used next generation mRNA sequencing on post mortem samples collected with 24 hours of death. They found that some genes were still active, suggesting that there is still some transcription after death. However, the reason as to why this occurs is still unclear.
This data has allowed scientists to predict post mortem RNA level changes for a variety of different tissues and organs from which future transcriptomic analyses could be calibrated. These changes in RNA levels after death may be a vital tool to help assist future criminal investigations.
Although more work still needs to be done to create a useful forensics tool, so far researchers are able to estimate the time since death from RNA levels.
Further investigation will look at longer post mortem periods, the age of the individual and the cause of death.