A human body’s cells continue to function even after the body dies, a study says.
An international team of scientists revealed that some genes actually become more active after death, the BBC reports. This can provide important data for other studies, but the researchers hope that it can become useful as a forensic tool, as well.
Inside a body’s cells, genes greatly influence life, controlled by various internal and external triggers. Understanding this gene activity gives a better look at what individual cells, tissues or organs are doing, either in sickness or in health.
Genes are kept in the DNA present in a human body’s cells, generating a molecule called an RNA transcript. These transcripts are what scientists often measure in a process called analysis transcriptomics. Obtaining samples for studies is quite difficult – blood is the easiest kind to get.
Therefore, scientists rely on other available samples such as tissues and organs removed after death. These post-mortem samples provide important insights into how the body works, but it remains unclear if these accurately represent what goes on when the body is alive. In addition, samples are rarely taken after death – bodies are stored until post-mortem examinations are completed, and sonly then can sampling take place.
Roderic Guigó, a computational biologist based at the Barcelona Institute for Science and Technology and his team decided to study this reliance on stored post-mortem samples. He said,
You would expect that with the death of the individual, there would be a decay in the activity of the genes.
The team used next generation mRNA sequencing on post-mortem samples collected within 24 hours of death, and on a set of blood samples collected from patients before death.
What the researchers found was surprising. Guigó said, “There is a reaction by the cells to the death of the individual. We see some pathways, some genes, that are activated and this means that sometime after death there is still some activity at the level of transcription.”
Why the genes remained active was not clear, but Guigó may have an explanation. “I would guess that one of the major changes is due to the cessation of flow of blood, therefore I would say probably the main environmental change is hypoxia, the lack of oxygen, but I don’t have the proof for this,” he said.
This might prove crucial in future criminal investigations, the researchers suggest. “We conclude there is a signature or a fingerprint in the pattern of gene expression after death that could eventually be used in forensic science, but we don’t pretend we have now a method that can be used in the field,” Guigó said. “It requires further investigation, longer post-mortem intervals, not only 24 hours, the age of the individual, the cause of death – all of these will need to be taken into account if we are to convert this into a useful tool.”
The study was published in Nature Communications.