I recently watched 'Rise of the Planet of the Apes' again, and decided to write about the errors the writers made about the science in it. I like the movie, and that's why I'm bothered by its faults so much. Let's go directly to the problems. (spoiler alert)
GENE THERAPY
The whole movie revolved around an experimental drug that was designed to combat Alzheimer's disease. The prime investigator explained that it was meant to increase the brain's ability to regenerate. This does make sense. Brain damage (caused by toxic build-up of amyloid beta peptides) underlies the symptoms of Alzheimer's, and our brain is currently not good at healing itself. In fact, virtually none of our organs and limbs can grow back, only certain tissues that need to be replaced fairly frequently (like blood and skin).
There is evidence that our ability to regenerate is somehow repressed. During development in the womb we possess much stronger ability to regenerate, and gradually lose this, possibly due to scar formation (ref1, ref2). So it may very well be possible to reactivate this system. Researchers have shown that brain regeneration in mice restores cognitive functions even if the toxic amyloid plaques are left intact (ref). Of course, regeneration of the brain cannot restore lost memories, so it is best to use such a therapy in an early stage of the disease.
In the movie, the man suffering from dementia was cured by the gene therapy. Huzzah!
However, the man needed regular administration of the drug to keep the dementia at bay. That would have been the case for drugs that function only as long as they remain in the patient's body. Most present-day drugs work like that, and that's probably why the writers have made this error. But the main researcher developing the therapy explained that it was a virus-mediated gene therapy. In such a therapy the drug is a DNA-modifying agent (a virus in this case). The DNA code underlies cellular functions, and when it is changed, cellular functions are changed. So when this agent does its job, and you see a positive response (i.e. the person is has regained lost functions), there is no reason to take it again. The cells are already fixed. It could only make things worse, by adding too many copies of a certain gene.
Only when the previous administration of the virus did not work because there was too little of it to affect all the target cells, only then would it make sense to administer the virus again.
The whole movie revolved around an experimental drug that was designed to combat Alzheimer's disease. The prime investigator explained that it was meant to increase the brain's ability to regenerate. This does make sense. Brain damage (caused by toxic build-up of amyloid beta peptides) underlies the symptoms of Alzheimer's, and our brain is currently not good at healing itself. In fact, virtually none of our organs and limbs can grow back, only certain tissues that need to be replaced fairly frequently (like blood and skin).
There is evidence that our ability to regenerate is somehow repressed. During development in the womb we possess much stronger ability to regenerate, and gradually lose this, possibly due to scar formation (ref1, ref2). So it may very well be possible to reactivate this system. Researchers have shown that brain regeneration in mice restores cognitive functions even if the toxic amyloid plaques are left intact (ref). Of course, regeneration of the brain cannot restore lost memories, so it is best to use such a therapy in an early stage of the disease.
In the movie, the man suffering from dementia was cured by the gene therapy. Huzzah!
However, the man needed regular administration of the drug to keep the dementia at bay. That would have been the case for drugs that function only as long as they remain in the patient's body. Most present-day drugs work like that, and that's probably why the writers have made this error. But the main researcher developing the therapy explained that it was a virus-mediated gene therapy. In such a therapy the drug is a DNA-modifying agent (a virus in this case). The DNA code underlies cellular functions, and when it is changed, cellular functions are changed. So when this agent does its job, and you see a positive response (i.e. the person is has regained lost functions), there is no reason to take it again. The cells are already fixed. It could only make things worse, by adding too many copies of a certain gene.
Only when the previous administration of the virus did not work because there was too little of it to affect all the target cells, only then would it make sense to administer the virus again.
IMMUNE SYSTEM
Eventually the therapy failed. The man's dementia came back.
This is possible, because the gene-therapy only made the brain create new brain cells, not remove the harmful amyloid plaques. Or prevent future accumulation. A therapy to truly cure dementia should couple enhanced regeneration with the expression of some enzymes that can break down the harmful substances in smaller bits that are safe.
It is also possible that the altering of the genetic code caused some disregulation in the long term. Especially when a drug like that hasn't been properly tested, unexpected side-effects may occur. One thing might be the formation of brain tumors, due to the fact that the gene therapy made the brain cells more likely to divide. Or perhaps brain cells that have one function (e.g. creating images) are suddenly growing in areas with other functions (e.g. making your limbs move).
In the movie it was neither of the above. The therapy failed because the immune system fought the virus. This is possible, though less of a problem for real-world gene therapies where you don't have to keep using the drug.
The problem is how the creators of the movie presented the immune system. For example, the researchers tested the drug on chimpanzees, and found that it worked. They commented that it was only logical because chimpanzees where known for their good immune system. As opposed to humans like the guy with Alzheimer's. This demonstrates some fundamental problem in understanding how the immune system works.
I have noticed the same thing when people talk about 'the ice-man' Wim Hof. Together with a science team it was tested how some techniques he used (meditation, certain breathing techniques and exposure to cold) could influence the immune system. One group of people performed the techniques for 10 days prior to the test, and the other group didn't. During the test, both groups received a bacterial protein, and the researchers examined the bodily responses. It was observed that the 'trained' group showed significantly lower levels of immune response-related proteins, as well as less flu-like symptoms than in the non-trained group (ref). Laymen then conclude that those techniques can improve your immune system. But of course, it is the other way round. That technique somehow inhibited the immune response. If the researchers replaced the bacterial protein with the actual pathogenic bacterium, the trained people would suffer more damage, and have a higher chance of dying.
SPEECH
The apes that received the gene therapy became smarter. It is possible that a genetic modification increasing the size of (certain parts) of the brain would increase intelligence. On the other hand, there has to be room in the skull for brain expansion. Young mammals have soft skulls which can expand if the brain requires room. But skulls of grown-up mammals are not so flexible, though I wouldn't say it's impossible. Bones are dynamic tissues, and so skulls might grow if the process of brain expansion doesn't happen too fast. Inheriting the modification from your mother (like Caesar did) would have solved that problem, but then the pelvis of the mother might be too small for the big head of the smart baby chimpanzee, and so it might not be able to exit the womb.
So the heads of the hairy apes should have become bigger, and something would probably have to be changed in the pelvis. But this does not diminish the fact that the increase in intelligence through genetic modification is really possible. And if, through some rare mutations or carelessness of the researchers the virus's replication ability was restored, it is possible to transmit this characteristic horizontally.
Stranger, to me, is the fact that the smartest chimpanzees get the ability to speak like humans. Real-life chimpanzees can be taught sign-language to a limited degree (e.g. Washoe, Kanzi). So they have some ability to understand language. A larger brain would make it possible to understand more complicated linguistic matters, but it would not make them speak like us. The reason is that their vocal tract does not allow it (ref). It would be very unlikely that the brain-growing virus would change the vocal tract when it hasn't been designed to do so.
CONCLUSION
This is but one example of movies that could have been great if they got the science right. If only they consulted a (life) scientist to check the script for errors. It doesn't even have to cost anything, I know I'd do it free of charge. I'm sure others would do too.
Update 22-02-15: researchers identified the genetic change that makes our brains bigger compared to our chimpanzee cousins. It is a 16-letter change in an enhancer of the FZD8 gene. They inserted the human enhancer + FZD8 gene into mice using pronuclear injection, and saw that it made the mice brains bigger compared to the normal (wt) mice, and compared to mice that received the chimpanzee enhancer + FZD8 gene. Awesome!
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