Though bringing people back from the dead is still a little beyond the reach of even the most morbidly ambitious scientists, new research has indicated that there is indeed some semblance of life after death, as some genes appear to “wake up” in the days after the fat lady sings. According to a new study published in the journal BioRxiv, analyzing the activity levels of these zombie genes could help investigators to more accurately determine a corpse’s time of death, which could, in turn, improve their chances of figuring out how they died.
During our brief mortal stint on this Earth, our DNA is continuously being read and transcribed by a compound called mRNA, which acts as an intermediary between our genetic information and the synthesis of proteins coded for by these genes. When we die, therefore, it seems logical to imagine that this process would simply grind to a halt.
However, after analyzing mRNA levels in tissues taken from the brains and livers of mice and zebrafish shortly after they had been “sacrificed,” the study authors found that levels of mRNA associated with certain genes actually spiked in the days after death, indicating an increase in transcription.
In total, they looked at 36,811 zebrafish genes and 37,368 mouse genes, discovering that mRNA was upregulated at various post-mortem intervals in 548 zebrafish genes and 515 mouse genes. Intriguingly, not all genes woke up at the same time, with some reaching a peak of undead activity 24 hours after death and others hitting their maximum a day later.
By analyzing these mRNA levels and working backward, the researchers found that they were able to accurately predict when each animal had died, and claim that if these results can be replicated in humans, then forensic investigators may be able to pinpoint the time of death down to a scale of minutes rather than days.
However, the process is not without complications, as the study authors were only able to successfully predict time of death using gene transcripts from the animals’ livers, but not their brains.
Regardless, the researchers believe they could well be onto something, and hope that their technique can one day be used not only to determine how long corpses have been dead for, but also to improve the success rate of human organ transplants. Indeed, since some of the genes that wake up after death are involved in regulating the body’s susceptibility to cancer, continuing this research could lead to a better understanding of why organ recipients tend to so regularly develop tumors.
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