Humanoid species that can consciously “read” each other's DNA: plausibility and limitations

Question

My premise is that there was a technologically advanced human-equivalent civilisation that eventually obliterated itself with weapons of mass destruction, but left behind a survivalist sect obsessed with genetic engineering, so that when the next wave of technologically advanced humans came along thousands of years later, it perceived those survivors as "primitive" and "feral" but endowed with Tarzan-like superpowers based on extremely evolved instincts that continue to adapt extremely fast between generations.

The remnant humans had engineered themselves to be able to "read" DNA like a sort of language, and thus be consciously able to maximise its offspring's Darwinian advantage by adding new instinctive abilities; ultimately, though, it's based on mate selection, and their mate selection involves an all-consuming mental effort resulting in behaviours similar to autism. I'd also like, for narrative purposes, to have this DNA-reading ability be blood-based and create an association with vampirism. I'm vaguely aware that it's not necessarily the optimal design from the scientific standpoint.

My question is, how generally plausible is "wiring" a nominally human brain to be able to interpret and, to a degree, manipulate DNA using the faculty of taste as input, and what would be the natural limitations if the general principle does work.

Answer 1

My experience with biology is that the brain is an amazingly good pattern and language machine. The bigger limit would be developing good organs for scanning DNA and relaying that information across nerves. Sensing "other" DNA and differentiating it from your own DNA (of which there is a lot of it in your body) could be a trick, with lots of false positives. A sense of "self" would be essential, at the DNA level.

Another interesting question is how does it decide fitness? The process of converting DNA to proteins (which actually do the real bio-mechanical work in our body) is terribly interconnected and complicated. It may be that the language is just too complicated to learn.

However, in such a post-apocalyptic universe, I'd consider a storyline where the obsessive genetic engineers "simplified" the DNA to make it more readable. Being overzealous, they simplified it "too much," creating a system which is inefficient compared to non-engineered organisms. They have to spend an inordinate amount of energy maintaining their genetic contents compared to their carefree monkey cousins. This could lead to a continuing struggle to develop "the best language" for DNA to take shape, where the language shapes the DNA, and then a generation later the DNA shapes how the next generation learns the language.

It might even lead to two castes: those which invoke an autistic-like all-consuming effort in their mate selection, and those whose genetic lines have already decayed to where they might as well just sit back and enjoy their life. Then, in the middle, you'd have a few who don't seem to fit the mold.

Answer 2

Humans or human like beings could communicate using DNA but there's a lot that would need to be added to human physiology to make that happen.

What the OP proposes to do shares significant similarities with how computers share and manipulate information. Some common language may bleed through.

Agree on a language

Assuming that arbitrary strings of DNA can be written and read, this little community will need to agree on a language. A string of CGAT base pairs, in and of themselves don't mean anything. A language to encode letters, numbers and other concepts will need to be developed.

Reading mechanism

There will be multiple stages required to read. First, the DNA strand will need to be extracted from its container. Second, the strand needs to be read then encoded into something the body will understand. Then, the message needs to be translated from a purely chemical signal into an electrical one for use in the brain. I have no idea how to even go about doing that but it will need to be done.

Sharing Mechanism

DNA is fairly fragile when exposed to sunlight or air so this group will want to protect the message in a virus coating or bacteria or some other kind of survivable container. Their genetic engineers should be able to choose a container that has high environmental resilience, easy message extraction and minimal requirements in terms of energy or materials. (Don't make a giant container if you don't need to.)

On a more macro level, messages will need to be passed between people directly or deposited somewhere and picked up later. Perhaps embedding a message container in a stable oil would work. A small gland somewhere on the head could handle secreting and reading messages.

Writing Mechanism

This is the inverse of the Reading Mechanism and I don't have a way of translating electrical impulses in the brain into DNA strands to be shared.

Defensive Mechanisms

Whenever DNA is used as a communication method, it is probe to be hijacked by Life. Viruses, bacteria... The designers will need to be careful about this sort of thing.

Answer 3

If you want this question to stay hard-science, then I am afraid you cannot have any creature, no matter how smart, to consciously read the genetic information. Our body goes on reading a lot of genetic information at very minute levels (the white blood cells for example, will try and destroy everything which has a DNA other than their own) but we are not consciously aware of it.

You can however read genetic information indirectly. Actually we do it all the time without knowing it.

What you are going to do is, that you are going to associate physical and psychological characteristics with genes. Long experience has shown those very intelligent humanoids which physical and psychological characteristics are controlled by which gene (remember, they used to be highly scientifically developed once!). So even without sucking the blood out of anyone, they can simply tell a lot of genetic information about someone by simply looking at them, listening to them and watching them go by daily activities.

They can also process the genetic information of ingested items (through specialised organs, as stated by members before me), and this information would give them a feeling of yes/no for their questions about a creature. For this we will need to limit our intelligent creature's genetic reading ability to mammals only. Whenever they eat a deer's meat, after some 1 hour or so, they have a feeling of knowing a lot of things about the deer's characteristics. They cannot read the DNA directly, but their DNA processing organs rather decode the genetic information and present it as a set of physical characteristics which can be understood by the creature.

For example, let's say Mr. Brrodd eats some deer meat. After one hour he can say "Ah, the deer we ate had slightly heavier build than most of the deer I have eaten in my life."