I'm building some alien cultures for my fictional universe. One race has advanced technology and culture enough to have accepted, regularly occurring, DNA modification available (EDIT: regularly occurring among the race as a whole. Individual adaptations take many years).

This race values intellect and advancement, seeing all other species as equal and as having something to teach them about the universe and their own unique perspectives. The main goal being to try and contact a "God" they've experienced glimpses of.

As thus, their modifications are peaceful in nature and are mostly used to make life easier for their society as a whole

  • ie. creating a more efficient way for their bodies to utilise calories/nutrients/macros

And to gain a deeper knowledge of other races

  • ie. living in the copies of physical forms of other species in their own daily life or in disguise on the other species' own planets

Another idea I had for energy intake/usage efficiency is using DNA modification to adapt skin cells to incorporate chlorophyll which allows the body to use sunlight for energy. I've also considered incorporating the ability to absorb kinetic energy from the surrounding environment (warmth/wind/impact/motion etc) to be utilised in the body also.

With these modifications in mind, what foods would these aliens' diets consist of to make up for the nutrients not gained from the sun/surrounding energies absorbed etc.?

Thanks in advance for your thoughts and answers! I look forward to the discussion.

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    $\begingroup$ The best things you could do with extensive gene modification is to create organisms able to utilize a wider array of amino acids, protein types, and organic molecules for energy; Also allowing tolerance of non-terrestrial biochemistry (so they could dwell among aliens). I might suggest doing this on a modular biochemistry basis, so you modify for a given environment then switch for a new one. But with that level of tech, alternate means would likely be available (nanites, symbiotic organisms, filtration devices/catalytic equipment) not requiring gene modifications. $\endgroup$
    – DWKraus
    Jan 7, 2021 at 3:20
  • $\begingroup$ This is a fantastic suggestion @DWKraus, I hadn't considered higher tech in the adaptations. As provided by the answer by jdunlop, evolving the microbiome of the gut sounds much like what you've suggested where the body is (relatively) quickly and efficiently adapted to each environment as these aliens travel between them. The tools you've suggested will be handy in making that happen. Thanks! $\endgroup$ Jan 7, 2021 at 4:03

2 Answers 2


Frame Challenge: Assumptions are being made in the question regarding DNA modification being a kind of magic.

Pretty Much a Normal Diet

It's a pretty common sci-fi trope, but DNA modification isn't magic. If the DNA in every cell in your body changed to that of a capuchin monkey right now, it would be some time before you noticed anything, and it wouldn't be that you turned into a capuchin monkey. If you change your DNA, your body is still what it always was. Changes made to germline cells (sperm, eggs) will change what the offspring develops into, but an adult organism cannot be transformed by changing their DNA.

What is likely to occur if you dramatically change the DNA of an adult organism is that they will die. DNA mostly codes for protein synthesis. If important proteins (for the adult organism) are excised or omitted, the organism will die before any changes to their appearance occur.

If your species wants to live in the bodies of other species, they would have to grow a cloned body of that species, and then somehow transfer their intelligence into it. This was a plot point in a lot of John Varley's works.

Mobile organism (typically human) photosynthesis has been covered on this StackExchange before, and the consensus is that even if you could expose all your skin to the sun (unlikely, since you need it to keep your insides in), it was perfectly sunny every day, and you didn't exert yourself, photosynthesis provides about 25% of the caloric energy necessary for adult human operation. Even if you "optimized" photosynthesis (difficult to outdo evolution in that regard) with DNA editing, bettering that performance is unlikely.

Similarly, for a non-sessile organism, extracting energy from wind or impact is going to provide a vanishingly small portion of the energy the organism requires. Extracting energy from warmth may actually be impossible for exothermic life, because it would violate the laws of thermodynamics.

Where your DNA-modifying race might come out ahead is optimizing intestinal flora and digestion to break down foods more efficiently and synthesize useful proteins, allowing (for example) a wholly plant-based died comprised mostly of sugars to power their metabolism. But that sounds kind of boring for any chefs in this society!

Edit: Dug into this a bit further, and if you dramatically change the DNA of an adult organism, they die very quickly. Within minutes, of massive anaphylactic shock and hemorrhage, as cells disintegrate.

  • $\begingroup$ Thanks @jdunlop, I'll look into optimisation of the microbiome within the gut to enhance energy and nutrient uptake, that's a great suggestion. I also appreciate your clarification of DNA modification NOT being magic. I don't want my novel to fall into the realm of Science Fantasy. I understood that DNA modification would take a long time to occur, and factored that into the alien world, where any changes made would be long-term. Not "regular" for a single individual, but rather regular as in accepted and occurring widely among the race as a whole. $\endgroup$ Jan 7, 2021 at 4:00
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    $\begingroup$ It was the "deeper knowledge of other races" one that prompted the first bit - there's pretty much no way you could transmute one adult member of a species into another by DNA editing - it would just be lethal. And condemning one's offspring to be forever unlike the rest of their species also seems like it'd be rough. $\endgroup$
    – jdunlop
    Jan 7, 2021 at 5:09
  • $\begingroup$ Luckily the offspring of this race goes through an external embryonic development process! DNA is collected from members of the species early in their development/prior to any modifications, and is used by curators to initiate the creation and development of future generations. But yes, with the complexities of the cell and the whole multicellular unit, I can see where DNA modification will hit many roadblocks. I'll have to search for a separate question on this topic specifically. Thanks for the insights. $\endgroup$ Jan 7, 2021 at 6:17

The possibilities of what might be achieved from genetic manipulation are mind boggling. What we see in the natural world is just a tiny fragment of what is biochemically possible.

The problem is knowing what DNA changes are required to produce the required bodily changes. Given the enormity of the possibilities gaining this knowledge would require god like capabilities.

In most cases that we are familiar with changes to adult DNA do not result in changes to the adult body but that is not written in stone. Changes to DNA in adult bodies can and do result in changes to those bodies. This can be seen in an uncontrolled form in cancer and in a more controlled form in the transformation of a caterpillar into a butterfly.

Concerning foods the world is your oyster so to speak. Any thing from the natural world might (theoretically!) be incorporated into a body and a lot else as well. Additional tissues and organs could be generated for dealing with a huge variety of substances. Bacteria like e-coli have "learnt" to be very adaptable and can survive from a wide range of different food chemical substances by activating different sets of enzymes.

In terms of chlorophyll this would be theoretically possible, however it would not be a sensible option as the amount of energy that could be gathered would be tiny.

So in summary, what foods are (ultimately) consumable is a function of what is available in the environment limited by chemistry and physics. I would stress again that the primary difficulty is finding the right DNA code to use. There are more possibilities than there are atoms in the universe by many orders of magnitude.


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