Defining “time of death” used to be a no-brainer: No breath, no circulation, no life. But scientists are constantly uncovering physical processes that continue post-mortem, forcing us to rethink what death actually entails. Researchers at the University of Washington, Seattle, recently discovered that genes — which encode the proteins needed for life to continue — are alive and kicking up to 48 hours after an organism bites the dust.
In a pair of papers published earlier this month in bioRxiv, a research team led by Peter Noble, Ph.D, and Alex Pozhitkov, Ph.D., discuss the sudden reawakening of genes in newly killed mice and zebrafish. In living organisms, gene activity is a given; cells, full of energy and functioning at peak capacity, are constantly “reading” genes and turning them into proteins to keep life afloat. But you wouldn’t expect that from a corpse. After all, what would be the point?
That’s the question Noble and Pozhitkov are trying to answer after realizing that 548 zebrafish genes and 515 mouse genes went into active mode after the individual organisms died. They measured this by looking at the level of mRNA — strands of “messenger data needed to turn active genes into proteins — still floating around in the cells. Long after the animals were killed, their cells kept making mRNA, and gene activity peaked about 24 hours after death.
The genes that were active in dead animals weren’t just the run-of-the-mill genes needed for everyday living. Of the genes that turned on immediately after death, many were associated with cancer, and some were — and this is pretty weird — genes associated with fetal development, which normally shut off once a baby is born. Could it represent the body’s last attempt at holding onto dear life? As of now, it’s too early to tell, but the findings do imply that the body continues living much longer after the person peaces out.
Right now, we define death as brain death; that is, when a person’s brain no longer supports independent breathing. Most people presume that brain death includes the end of consciousness, too.
The new findings by Noble and Pozhitkov don’t contest the death of consciousness, but they do add to a growing body of evidence that, conscious or not, bodies can stay literally woke long after their owners have died.Photos via solene Mest*/Flickr