There is a "zombie gene" in the human brain, and it becomes active only after death

This article is converted Medicine original, reproduced please indicate the source Author: Yun Introduction: man after death is not all cells ceased its activities, on the contrary, studies have found that glial cells were grown in a few hours after death, and Long arm-shaped appendages grow, and their activity will reach the highest peak 12 hours after death.

Zombie genes, at first sound, seem very scary.

In fact, it is a cell that can continue to function after death, and it performs better than before.

Within a few hours after death, certain cells in the human brain are still active.

According to the latest research, gene expression in certain cells actually increases after death.

The research was published in the journal "Scientific Reports" with the title "Selective time-dependent changes in activity and cell-specific gene expression in human postmortem brain".

The researchers collected fresh brain tissue during routine brain surgery, and measured and analyzed it multiple times after its resection to simulate the post-mortem interval.

They found that gene expression in some cells increased after death.

These "zombie genes"-those genes whose expression increases in the post-mortem interval-are a characteristic of the cell.

Such cells are called glial cells, which are inflammatory cells.

Researchers have observed that glial cells will grow within a few hours after death, and grow arm-like appendages, and their activity will reach a peak in about 12 hours.

Figure After the human brain dies, zombie genes begin to express at a higher level.
This feature of glial cells growing after death is not surprising, because they are inflammatory cells themselves, and their job is to clean things after brain injury.

The most important significance of this discovery is that most studies on human brain tissue after death have not paid attention to related gene expression or cell activity; most studies assume that when the heart stops beating, everything in the brain stops.

In addition, about 80% of the analyzed genes will remain relatively stable within 24 hours.

These genes are often called housekeeping genes and are responsible for providing basic cell functions.

A group of genes that exist in neurons and are closely related to the activities of the human brain will rapidly degenerate within a few hours after death.

Researchers said: These genes are very important for studying diseases such as schizophrenia and Alzheimer's disease.

There are many studies on "zombie genes", for example: "zombie genes" attempt to save the dead.
Biologists from the University of Washington tested post-mortem samples of mice and zebrafish by monitoring the presence of messenger RNA in these animals.
Level to measure gene activity-an increase in messenger RNA indicates that there are more active genes.

It was found that 1063 genes were still active 24 hours after the organism died.

Not only that, although some genes decrease in activity within a few hours after death, in fact most of them increase in activity for up to 4 days after death.

The most active genes are related to immune function involved in inflammation.

These genes play a role in emergency situations, such as helping the organism fight an incoming infection.

The activity of other genes is even more surprising.
For example, scientists have observed that developmental genes are “turned on” (or activated) after death.

What surprised the researchers the most was that within a few days after death, they even checked the expression of unexpressed gene sequences.
The functions of these gene sequences that were activated only after death and the birth of new life, embryos Developmental genes have similar functions.

Some scientists regard this gene that is activated after death as a "zombie gene.
" It is activated after death to try to save the cell, regenerate the cell, and achieve the effect of saving the dead.

Although this experiment was performed on mice, scientists have discovered the same mechanism in humans after death.

Another potential application of this "zombie gene" research is death identification in forensic medicine.

Although many biological, chemical, and physical indicators can be used to determine the time of death, most indicators in the forensic analysis of murder victims are not very accurate.

However, the gene activity measurement method used in this new study can be applied to forensic identification to accurately predict the time of death of the victim.

The "zombie gene" in elephants is the key to cancer resistance.
In 2015, researchers at the University of Utah in the United States found that the number of cancer cells in elephants is about 100 times that of humans, but the number of copies of the P53 gene that inhibits cancer in elephants is large.
Up to 20, while humans and most other animals have only one.

P53 can identify damaged and irreparable deoxyribonucleic acid (DNA) in time, and cause the cell death to prevent it from developing into cancer cells.

The seemingly scary but interesting "zombie genes" are of great significance for scientists to study death, and studying death helps people better understand life.

Reference materials: [1] [2] https://medicalxpress.
com/news/2021-03-zombie-genes-life-brain- death.
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