From Birth to Death: Some Genes Stay Active After We Die, New Research Shows
What happens to our genes when we die? They stop working, would be a reasonable assumption. But a surprising, new study shows that even when our bodies show no signs of life, genes can continue to be active.
Currently, little is known about how death affects gene expression. The presence of a gene in our DNA doesn't automatically guarantee an end result, like eye color. Rather, it's through the process of gene expression that they essentially provide a plan for how cells will function. And some of our genes are active, or expressed, while others are not.
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A better understanding of exactly when our genes cease their activity could help forensic scientists pinpoint time of death, and add to what we know about how genes work.
To determine whether genes remain active after death, a group of international researchers measured how strongly a gene was being expressed. The team used donated tissue samples from the American Genotype-Tissue Expression project, a government-funded project to study genetics that includes tissue samples from patients (both alive and dead).
The researchers looked at 36 blood and tissue samples from 540 deceased donors, who had been dead for up to 29 hours, and reviewed records on how soon the specimens were collected after death. The paper was
According to the study, published in February in Nature, activity didn't stop all at once. Gene expression in muscle tissue, for example, stopped soon after death, but activity in colon tissue increased.
“The response to the death of the organism is quite tissue specific,” study co-author and molecular biologist Roderic Guigó of the Center for Genomic Regulation in Barcelona, Spain, told Science magazine.
Guigó and his team determined that subcutaneous fat, lung, thyroid and skin tissues most accurately reflected someone's time of death.
Based on their findings, the team created an algorithm to better estimate the time of death that's accurate to about nine minutes, according to microbial ecologist Jennifer DeBruyn, of the University of Tennessee in Knoxville. DeBruyn was not involved in the study but explained to Science News that this finding could help better identify someone's time of death.
Currently, forensic scientists look at internal body temperature, measure muscle stiffness and study environmental factors to determine when someone died. But improving accuracy is a constant focus for the community. Solving the biological mystery of how our genes behave after death could help solve criminal mysteries, too.