A recent study that looked at the genes of zebrafish and mice after death found that hundreds of their genes became active postmortem. The study does not suggest the living dead may soon walk among us, but it does shed new light on potential ways to help human health.
Surprising Study Results
Researchers at the University of Washington evaluated over 1000 genes of recently deceased mice and zebrafish. They tracked changes in the genes for 4 days in the fish and 2 days in the mice.
Instead of shutting down, as would be expected, the researchers found that hundreds of the genes actually increased their activity within the first 24 hours after death. Most genes gradually decreased activity after that, but some of the zebrafish genes in particular remained active 4 days following death.
Many of these postmortem genes are related to stress responses in the body, such as promoting inflammation, activating the immune system and counteracting stress. This seems somewhat logical as the body has recently expired and could be undergoing a final stress reaction.
But other unexpected genes also became active. The most surprising were genes that assist embryonic development. These genes typically turn off after birth as they are no longer needed. The researchers believe this postmortem reawakening could be because the cellular conditions in a newly dead corpse are similar to those in embryos.
Genes that promote cancer also became more active posthumously. This could help explain why people who receive organ transplants double their risk of developing cancer.
Potential Benefits for Human Health
Zebrafish share 70 percent of the genetic code of humans. They’re often used for genetic research because it’s fairly easy to link what happens on a zebrafish genome to the equivalent activity on a human genome.
The next step for the researchers will be to see how these active postmortem genes match up to humans and how it can benefit our health.
The researchers suggest that our bodies may have evolved this way to allow for possiblehealing or resuscitation after severe injury. For instance, the upregulated inflammation response genes after death will signal that there’s been an injury to the still alive cells in the body.
By looking more closely at the activated cancer genes, there is the potential to find better ways of transplanting organs and tissues without increasing the recipient’s cancer risk. It may also be possible to find a way to stop or reverse the activation of those genes in order to heal cancer in a living person.
In a follow-up study, the researchers showed another use for the upregulated genes can be to accurately predict the time of a person’s death. This could help in the investigation of suspicious deaths or murders. Current forensic science relies on evidence that’s not related to a deceased body, such as when the person was last seen or when they made their last cell phone call. Being able to pinpoint the time of death would benefit investigations.
This research may not be able to answer any of our larger questions about what awaits us after death, but it has the potential to enhance our lives while we’re still here.