My story is Dystopian placed after a nuclear fallout, in a small group of isolated cities with futuristic technology. The plotline is that the government is kidnapping children with disabilities, young teens that commit minor crimes, and kids whose parents died or went against the government and were imprisoned. They do experimentation on the kids, but once they are teens and adults, they put them in a place called The Underground, a series of tunnels, subways stations, and basements beneath a destroyed city from our era. They can not escape to the surface due to left over radiation.

I know that they are experimenting with diseases to figure out how to eliminate various viruses and bacteria as well as birth disorders, but I assume that to try and fix birth disorders they would need to edit the DNA. Is it possible with our current technology or tech we could build in the next hundred-ish years to modify a kid's DNA after they are born, and if so up to what age? I assume it would stop working after a certain age and that's why they discard the teenagers and adults. I already know that you stop producing more T-cells as a teen, so that is part of the reason they don't use them for viral experiments, but I need more reasons.

I also welcome any fun ideas you have with this prompt, it's one I really enjoy. :)

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    $\begingroup$ Birth defects are not treatable by genetics. They can be modified with surgery, but short of laying down an extracellular matrix and populating it with stem cells, it's developmental. That being said, while getting a stable and reproducible genetic change with CRISPR requires a new generation, viruses delivering plasmid-like DNA can be directly affect individual infected cells. T cells are produced throughout life, so I'm not sure what cells you are referring to. $\endgroup$
    – DWKraus
    Oct 23, 2020 at 3:13
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    $\begingroup$ Oh, are they? The site I looked at says they aren't. I'll link it, idk. discovermagazine.com/health/… $\endgroup$ Oct 23, 2020 at 3:25
  • $\begingroup$ To get a better understand of what you can and can not do with gene therapy, it is first important to understand that genetics is more chemistry than engineering. You can change the way individual cells behave, but you can not cause macroscopic changes to the body. $\endgroup$
    – Philipp
    Oct 23, 2020 at 14:24

3 Answers 3



What you need is CRISPR-Cas. It's a potentially world changing DNA technique. The techniques to change DNA can mostly choose one of the following attributes: fast, cheap, precise. If they are precise, they are often taking a long time and are expensive. CRISPR-Cas, if it's truly working (which seems to be the case) is fast, cheap, very precise and can be done at any moment. Before conception, during pregnancy and any time after birth right up until they die of old age.

CRISPR-Cas works by using the enzymes bacteria make for defence. If a bacteria survives a virus attack, it'll keep part of the viruses DNA within an enzyme. If this enzyme detects that very specific code of DNA, it'll rip it out and replace it with garbage DNA. This will kill the virus or render it harmless.

We can now high-jack this process. We can change the specific DNA that need to be replaced, as well as what it'll be replaced with. This means that, for example, if your eye colour has one specific DNA strain, we can change it for another, or something completely different. Most attributes we get from DNA is more complex and not one specific line of 'code' in the DNA, but even the small things can have huge ramifications.

From DNA we make RNA. RNA is like a bit of code that is mostly used for the creation of enzymes. These enzymes do a lot of work in the body. Now imagine someone with a thyroid gland defect. This can impair growth, metabolism, temperature, cholesterol and much more. In a few CRISPR-CAS therapies you can potentially change the whole function of this gland.

Research is now mostly focused on birth defects. Preventing MS, dementia, immune disease and much more. The list is pretty big.

Potentially you can put grown people's bodies back in a state that the bodies think they're twelve years old, giving them a growth spurt again. Or their brains making rapid connections. Give them bio-luminous skin. Or give them the ability to lose less telomeres and slow down/prevent aging.

For your story, the research might be most interesting for children. Older people might be more stable, but DNA is a complex and tricky thing. Some research might be more suited for children, especially with their still growing immune systems. We can see this with strength against some diseases. They are an inconvenience for children, but potentially deadly for anyone who didn't get the disease when they were kids. It is then much easier to test on kids than to try to adapt grown men first with a technique we aren't even sure will be able to work that miracle at a certain time.

Do keep in mind that you can only work with the available chromosomes. You can't add more chromosomes. I'm not sure if you can lengthen or shorten the DNA strain you replace, but I thought I read somewhere it's possible.

In short is the following what you need:

  • A bacteria you can infect with the desired change of DNA to produce the enzyme, or a direct way of producing such enzymes.
  • A DNA sequence of the person you want to change the DNA from. Potentially you can have some more meta DNA for a larger group you can change, but if it's only a little bit different the DNA won't be replaced.
  • Access to the person to inject the enzyme in enough quantities.
  • DNA knowledge. This is something that would be near impossible to do randomly. It would be like trying to break an encrypted password, but instead of working with 0 and 1 you need to work with about 5 values.
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    $\begingroup$ It's not quite true that the changes can be "done at any time". If you change genes so that they have 6 arms, but do so at 12 years of age... they won't grow 4 more arms. That whole bundle of genes has already been expressed, and merely changing it won't change the organism. Other genes that are constantly being expressed (hair color, perhaps) can be changed at any point and the results can be seen pretty quickly. $\endgroup$
    – John O
    Oct 23, 2020 at 13:34
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    $\begingroup$ @JohnO Great point - the underlying DNA can be changed at any time, but it won't do anything if that sequence doesn't get transcribed anymore. There are many genes where knockouts are "embryonic lethal", meaning they are completely essential during organism development, although silencing the gene in an adult specimen has no major effects. $\endgroup$ Oct 23, 2020 at 14:20
  • $\begingroup$ @JohnO it wasn't my intention to make this part confusing. I hoped the kids part would give this clarity. Changing DNA can happen at any point, but expression depends on what you're doing and timing. That is why my examples are talking about things that can be done at any time, or preventing. MS for example is potentially easy to prevent if it's not started. If it has started you can halt it, but to regenerate myelin you suddenly need to change a lot more. $\endgroup$
    – Trioxidane
    Oct 23, 2020 at 14:21
  • $\begingroup$ CRISPR-Cas9 is actually mostly used in oocytes or embryos. Gene editing in general can also be done in grown organisms (and has been in clinical research before CRISPR even existed). But for OP’s case of fixing “birth disorders” it would be ineffective, as noted by the other comments. $\endgroup$ Oct 23, 2020 at 16:31

There are two different concepts, germline genetic engineering and somatic gene therapy.

  • Germline gene therapy changes the sperm and egg, before conception, and therefore all the cells in the individual.
  • Somatic gene therapy introduces the change to other cells -- after birth and therefore not as complete.

As I understand it, germline therapy would be easier to do once you have the changed DNA ready, but also with much greater potential of disaster.

You could assume that germline experiments were done with your characters and that these experiments were declared finished after a decade or so. The change was done before conception and the experimenters observed the first years of their lives, no more.


Technically, you can alter anyone's DNA at any time to produce a mutation in a cell, or possibly lots of cells. You could alter the DNA of the corpse (at least some of the cells). But from the details, you want to know when altering DNA will cease to produce noticeable effects in the subject.

It depends.

DNA codes for protein. Protein is generated through your life, but some more consistently than others. For instance, a mutation that causes a malformed heart would have to be fixed very early prenatally to affect the child; they would have to resort to more conventional means to fix this child, but they might engage in genetic engineering so that the child did not pass on the mutation. But cystic fibrosis and albinism turn on proteins that are generated throughout life. You could edit those genes at any point, though there might be residual effects that the current production of proteins will not cure. Also you might need to separately target the gonad cells to ensure the child did not pass the genes on.


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