Life after death exists - sort of. A new study finds that some #genes become more active after death, according to the BBC.
Worldwide team of scientists led by Roderic Guigó at the Centre for Genomic Regulation in Barcelona showed that changes in gene expression in different tissues triggered by death can be used to predict the time of death of an individual.
Some studies have even suggested human consciousness can continue on after the medical definition of death - defined by the loss of heart and respiratory function.
Understanding gene activity provides a flawless insight into what an individual cell, tissue or organ is doing, in health and in disease.
To understand the tissue-specific changes to gene expression following the death of a person, Roderic Guigó and his colleagues studied RNA-sequencing data of over 7,000 samples from 36 different tissues obtained from 540 donor within the GTEx project. However, this study dealt with humans. "At a cellular level, death is a cascade of events affecting biological processes at different timescales", he says, and genes control that cascade.
Scientists have found a "cascade" of genetic changes which happen when we die, which fuel the death of cells in the body and the shutdown of the immune system.
Lead author Dr Pedro Ferreira, from the University of Porto in Portugal, said that they have found that many genes change expression over relatively short post-mortem intervals, in a largely tissue specific manner. For example, a set of genes that tended to promote the growth of cancer reactivated.
"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.
Rigor mortis, where the muscles stiffen or relax after death, provides the current best time of death but the new genetic method uses tissue which is easily available, offering more options in crime cases where remains are found instead of a whole body. These transcripts are what scientists often measure in a process called analysis transcriptomics. "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". He clarifies that muscle genes had quick lifts or drops in activity, while gene activity in the mind and spleen didn't change much with time. Their study establishes a baseline against which future transcriptomics can be checked.
Inside a body's cells, genes greatly influence life, controlled by various internal and external triggers.
Although the exact reason the genes remained active was unclear, Prof Guigó does have one possible 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".