We are used to considering our own body and mind as our inalienable property. But, in fact, any of us is a fusion of many organisms. Another human personality may well be among them. This is written by mixstuff.ru with reference to BBC Future.
Once upon a time, it was much easier for a person to talk about his origin: dad met mom, they spent a magical night together, and then a screaming and kicking human cub appeared from a tiny fertilized egg to the world. We are 50 percent from mom, 50 percent from dad and 100 percent from ourselves.
Everything would be fine, but these days this simple story is overgrown with many complex details. In addition to parental genes, we are a mosaic of a wide variety of viruses, bacteria and, possibly, other creatures like us.
If, for example, you have a twin, then you can easily carry parts of his body or brain. Even more amazing, they can influence your actions and decisions.
“People are not unitary individuals, but superorganisms,” says Peter Kamer, a specialist at the University of Prague. "Quite a number of different human and non-human individuals are constantly fighting within us for control."
All of this may sound threatening, but it is, and it has always been. Bacteria in the abdomen can produce neurotransmitters that can alter mood, awaken or suppress appetite, or make you crave for a particular food.
Infection with the Toxoplasma gondi parasite, at the same time, can kill.
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In nature, there are microorganisms that, penetrating into the rat's brain, inspire sympathy for cats - it’s easy to guess how this ends.
But people can also be infected in a similar way and develop an irresistible passion for risk and danger. This, in turn, increases the likelihood of developing schizophrenia, depression and suicidal tendencies. According to the BBC, about a third of the meat produced in Britain is infected with this parasite.
From all of the above, we can conclude that our actions cannot be considered one hundred percent ours. But the most terrifying thing is not the influence of tiny microbes on our decisions, but the fact that inside each of us there may be a different human personality.
The most obvious case is conjoined twins. But, as Kramer says, even regular twins can share organs. In early pregnancy, twins or triplets can exchange cells. Once this phenomenon was considered rare, but now experts know that there is nothing extraordinary in it.
Approximately 8% of non-identical twins and 21% of triplets, for example, have not one, but two blood groups - one is produced by a person's own cells, the other is "foreign", borrowed from a brother / sister. In other words, these people can be called chimeras - the fusion of two bodies, and such fusion can occur in different organs of a person, including the brain.
If the chimera affects the brain, then it can threaten with serious consequences. We know that proper communication between certain parts of the brain is critical to the functions they perform. However, if there are “foreign” cells in the brain, controlled by a different set of genes, then a failure occurs.
This may explain the fact that there are many left-handers among twins - a feature associated with the work of the right and left hemispheres. Perhaps it is chimerism that upsets the balance.
But even if you've never had a twin, there are many other ways that foreign cells can enter your body. For example, it is possible that at first there were two of you in the mother's womb, but in the early stages of development you “merged” into one organism.
In such cases, the fetus develops normally in all respects, but nevertheless, it bears the genetic traces of another person. There is a known case when, after a genetic examination, it turned out that a woman is not the biological mother of her own children.
Another option is that the cells of the older child can remain in the mother's body and, after the next conception, enter the body of the younger child.
Lee Nelson, a professor at the University of Washington, as a result of his research, found that even an adult is not immune from "genetic invasion." He examined the brain tissue of a woman, 63 percent of which was male. Scientists have found male DNA in different parts of her brain.
Most likely, these cells came to her from the child: in some incomprehensible way, the son's stem cells made their way through the placenta and completed the path in the mother's brain.
Another striking thing is that these cells significantly reduced a woman's risk of developing Alzheimer's disease.
It turns out that it is practically impossible to fully understand the behavior of even oneself, let alone another person, because our personalities have too many “components”.