It may seem that we know what death is. At least we think so. But the simple definition of death - stopping the body's life - does not take into account how strange our bodies actually are. As Peter Noble, former professor at the University of Alabama, told Discover, scientists really know almost nothing about what happens when a person dies. Noble knows firsthand that surprises await the one who studies death: for example, he helped discover that sleeping genes can be activated several hours or even days after death. But how and why does this happen?
Creepy Zombie Genes
A gene is a set of chemical instructions made up of DNA that tells the body how to do something. When a gene is activated, these chemical instructions are transcribed by RNA, and cells can then use the copied sequence as a framework for building complex molecules. If you imagine that a gene is a recipe in a cookbook, then activation is a list of ingredients necessary for cooking.
During the study, Noble and colleagues at the University of Washington tested a technique for measuring gene activity. As a control, tissues of recently deceased zebras were analyzed. Researchers expected to see a steady decline in new gene copies as cell activity declined. However, they found something surprising - with some notable exceptions. After the zebras died, about one percent of their genes came to life. Everything looked as if the cells were preparing to build something.
The idea that genes are activated after the death of the body is incredible, so the researchers decided that the reason for the results was a malfunction of the equipment. But repeated tests conducted on fish, and then on mice, continued to confirm the impossible: genes are activated several hours or even days after the death of the body. Scientists' findings were met with skepticism until a group of researchers led by Roderick Guigo of the Barcelona Center for Genomic Regulation also discovered posthumous gene activity, this time in humans. Guigo and his team studied gene regulation by analyzing the tissues of people who donated their bodies after death. Their work was already in full swing when Noble's article was published, so they were not surprised by the results of his team.
What genes are activated after death?
In the future, the results can give scientists a better understanding of how genes work in living organisms and how organs change at the molecular level after death. In the course of the work, the researchers also found that different genes are activated at different intervals after death - one of them can be activated regularly six hours after death, while the other can be activated after 24 hours. Forensic experts could use this information to more accurately estimate the time of death.
Despite the possibilities offered by research, the reason why genes are activated after death is unknown. Scientists do not exclude that the key to the solution may lie in the types of these genes. Although none of the zombie genes seems to lead to physical changes after death, many of them are associated with activities that are usually strictly regulated or suppressed by the body. These include genes that are responsible for the beginning of the formation of the spine - if you have it, then a new one is not needed. Other genes that are activated after death are associated with the development of cancer. In general, the results of studies have shown that death is a more subtle process than previously thought. Death does not mean that all billions of cells in the body instantly stop working. The onset of death means that they stop working together. The hours and days during which these bonds break up and life fades away are new frontiers for science.
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