I'm building a world with humans being genetically engineered species, created by certain advanced Alien civilization ("gods", Creators etc ...) like in the Sumerian hypothesis, but with a twist: those "gods" created certain dormant genetic code in human DNA, in order to protect their secrets.

Whenever certain human being develops thought patterns that could get them near those secrets, this dormant genetic code is activated and cancer develops killing said human being.

I need a biological reality check on this, i.e. is such mechanism plausible according to current scientific knowledge, and if not any suggestion how to implement something similar is appreciated.

EDIT : For those wandering why cancer (it is relatively slow killer, except in some forms), there are several reasons. First, secret knowledge in this case is not easily transferable and it could not be expressed in current human languages(s) . It is not 2+2=4, E=mc^2, molecules are made of atoms etc ... It is more of certain state of mind, and to describe insights from it you would need some super-language not comprehensible by current mankind, just like apes could not understand our language except maybe basic concepts. Therefore, there is no need for quick kill. Second, cancer is still mysterious disease and causes for it are not readily understood (we know some risk factors, but not exact chain of cause-effect for most types) . Therefore, people dying from it would not be so strange, compared to sudden heart attacks in otherwise healthy individuals (autopsies and all included) . Thirdly, I aim for dark, gloomy and desperate world, with those nearing the truth suddenly realizing that shiny goal that looked so close and within the grasp is taken away from them .

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    $\begingroup$ Does it have to be cancer? Dementia (or alzheimer) would make sense as well I think, certain thoughts could trigger synapses to detoriate or some similar scenario. $\endgroup$ – Backup Plan Sep 27 at 7:05
  • $\begingroup$ @BackupPlan Cancer would be preferable, I will edit question to explain why. $\endgroup$ – rs.29 Sep 27 at 19:53
  • $\begingroup$ In light of your edit, does that mechanism need to be discreet and appear natural? $\endgroup$ – Teleporting Goat Sep 27 at 20:14
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    $\begingroup$ @TeleportingGoat Well, idea is that "enlightened" humans (those getting close to truth) get mortally sick throughout the history, and this does not raise alarm, except for passing suspicion that could not be confirmed by concrete evidence. $\endgroup$ – rs.29 Sep 27 at 20:31

Whenever certain human being develops thought patterns that could get him near those secrets, this dormant genetic code is activated and cancer develops killing said human being.

Thoughts cannot directly activate genetic code.

However, thoughts and more generally mental states can activate the secretion of certain neurotransmitters, like what happens when through meditation one can relax and reach a state of well being.

Those neurotransmitter can influence the cellular activity and also genetic expression. For example it is known that prolonged stress has a detrimental effect on the immune system.

It's not far fetched then to assume that certain thoughts can stimulate the production of certain endogenous molecules which, stimulating certain cells, can lead to the development of cancer.

However please note that cancer takes a long time to kill, and until that happens the human in question can still access and use those secrets. For a rapid death a stroke or a heart attack is way more effective, and those also can be caused by thoughts.

  • $\begingroup$ Interesting idea. As for cancer, it is more insidious. Human in question didn't discover secret in the form of information ( 2+2=4 , yay ) . It is more of inexpressible secret,, state of mind that could get him to "be like gods" . similar to meditation you mentioned. $\endgroup$ – rs.29 Sep 27 at 5:12

Yes, but I wouldn't choose cancer.

First, cancer is possibly one of the worst ways to kill a human in your case, because it progresses so slowly. Someone with cancer would have time to tell everyone, document their findings, and still have all of their cognitive function for most of the time before their death. It could take years to kill someone with cancer. If you want to silence someone, there are better ways. Target memory, sanity, or vital organs directly.

Secondly, yes, a thought can trigger a lot of physical things in your body. Thinking of the person you love or about that important exam tomorrow can release different kinds of hormones that impact the rest of your body.

If hormones can make a uterus "shut down" after a certain age, it shouldn't be so hard to add a "killswitch" on the heart or the liver, so that when certain hormones are released in a certain quantity your vital functions would stop working.

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    $\begingroup$ Agree that the need to kill quickly does not line up at all with cancer. Even the fastest cancers take weeks/months to kill, and that's from the time of diagnosis, which typically happens well after the cancer has taken root and started causing problems. If you need to go from the "cancer causing event" to death, the process will take even longer. $\endgroup$ – Nuclear Wang Sep 27 at 13:29
  • $\begingroup$ I don't need anyone to be killed promptly, because this kind of "knowledge" could not be transmitted by ordinary language. But thanks for your insight. $\endgroup$ – rs.29 Sep 27 at 19:52

All (or nearly all) human beings have minds that are constructed from the same basic template. (People who don't are usually very sick, and many don't live long at all.) State of the art (in 2019) neuroscience has an incomplete and very rough outline of what this template looks like - we have figured out "this is where the visual cortex is, there's the Wernicke area, etc" and we know what processes these areas are associated with.

However, we essentially have no idea how the individual areas work. We can tell you what they do, generally, but not how. Similarly, while we have identified many of the genes involved in the formation and fetal development of the brain, you can forget about being able to look at the human genome, and say "These specific genes are responsible for building the brain structures that allow you to see, and here is the detailed explanation of the organogenesis processes these genes control that builds the structure".

Modern medicine, however, has only known how DNA works for about 60-70ish years (since the 1950's). Okay, suppose your aliens have had thousands of years to study the field of genetic fetal development and neurobiology. They could use genetic and organogenetic engineering to design new brain structures, and then figure out how to write the DNA that will turn into those structures in a human being.

So you give humans a fictitious additional functional area in the brain. Its function is (to the humans in the story) unclear, but damage to the area usually causes things to go awry in a technobabblish way that unbalances the endocrine system and somehow leads to cancer. In actuality, of course, the function of this new lobe is to scan the person's thoughts for Forbidden Knowledge, and send a 'self destruct' signal that the body has also been engineered to listen for and disable key anti-cancer protections.

This also provides a plot hook, because now there are several ways this mechanism could be defeated. One, traumatic brain injury inactivates the trap. Two, doctors develop neurosurgery to deactivate the area (they can figure out the area is killing people and the surgery seems to help, but they don't know why). Three, damage to the endocrine system (such as can happen in chemotherapy or a few other ways) can prevent the kill switch from working. There are probably more.


Pure thoughts cannot do that. Physiologically, thoughts are electric and chemical activity in neurons - but even the chemical activity is the same independently of the exact content of the thought. So, if your humans are imagining a geometric figure, that will produce a certain firing pattern of neurons in certain brain areas, such as parts of the visual system - but you cannot make triangles a dangerous figure and leave squares a nondangerous one, since these will trigger roughly the same kind of activity, just in different neurons.

There is a way you could go, but it is through emotions. In the brain, emotions are a kind of neuronal activity, just like the thoughts, but they can also lead to the production of hormones. For example, anxiety is connected to ACTH production in the pituitary gland (which then cascades into the production of other hormones in the body). Frequent anxiety is famously a cause for epigenetic changes, there was a seminal study on rat pups inheriting anxiety from stepmothers, not through genes but through an epigenetic mechanism triggered by absence of calming behavior in their anxious stepmothers.

It is also possible, and common, to trigger emotions through thoughts. If you go to bed thinking that tomorrow, you will have an important exam you haven't learned for, you'll be anxious even though there will be nothing in your physical environment that's different from every other night. So, on that front, you might have some success.

The problem comes, again, from thought type vs. thought content. The brain's activity is localized in different areas when you are thinking about geometric shapes as opposed to listening to a song - but if you were go off that only, you would have to make all thinking about shapes dangerous (or all listening to music). Alternatively, you could say that the thoughts you need cause a certain emotion, and connect the disease to that emotion - but then, it will be triggered by all occasions of having that emotion, not just the ones caused by thoughts about the godly technology.

Since this is fiction and you have genetically engineered humans, you could make it work with some handwavium. You would need to add to the human body a special new emotion, that normal humans don't have. This emotion triggers a new hormone, engineered to have some effect on the human body. And this emotion is so specific that it can only be triggered by having a thought about the godly technology.

A plausible scenario of that kind would be to add a new level of insight. In real humans, the feeling of "X is true" is an emotion - it is just a pattern of brain activity that happens in our emotional centers when we encounter a thought we believe to be true. (Believe as in "faith" and "certainty", not as in supposing it should be true). So, add a new emotion derived from this one, which only happens when the engineered humans recognize not an ordinary truth, but a truth about the divine mechanism of the universe. You can add some graphic description of mythical extase there, that's highly plausible for an emotion. It will trigger your neurotransmitter, which will do its job wherever it needs to - you can actually decide on the duration of the human's life after the insight by picking your preferred cancer.

As a side effect, since our normal emotion of certainty occurs when we think something is true (regardless of whether it's objectively true), this will probably be also the case for the engineered emotion. So for the divine insight, it will also be plausible to not matter if the engineered human had a correct or incorrect insight about the way the gods function - if they live on Olymp, but he wakes up and is struck by the thought "I'm sure they live on Atlantis", the killswitch will also be triggered. That gives you a good deterrent of even trying to have thoughts in this direction, and even if a brave scholar puts up a theory and dies for it several months or years later, his disciples won't know if it was really true.


Some medicos today do think that cancer (and, unrelatedly, heart disease) is caused by stress.

In fact, "stress" is, essentially, "something you think".

You could absolutely play this in your story that, yes, it turns out cancers were caused by a mental situation; your future geneticists played this factor up to the extreme.


People are wrong about thoughts not being able to kill. It is well documented in humans and animals that mammals can literally die of a broken heart. (Ok, we can be pedantic like rumtscho's good answer and say that it's technically not the thought that kills, it's a follow-on process involving emotions and/or important glands, etc.)

Also, the power of suggestion can do amazing things. My brother in law had warts on his hand cured by hypnosis. Placebos can cure, and they can sicken (people that think they got a drug but did not, report the same side effects as people who really got the drug). People can become sick if they truly believe in the curse of a shaman.

So yes, it makes sense that a certain condition/pattern in the brain, indicating that person is having particular thoughts or has obtained particular knowledge, could trigger their death. The most straight-forward way I see is if that pattern was closely linked to the pattern that occurs in somebody that dies of a broken heart. In other words, it causes a depression so deep and sudden that the person dies of heart failure within 2-3 days of their revelation.


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