How to Write Biology in Science Fiction, Part 1: DNA

I had originally intended to make a single post about evolution in science fiction, but I quickly realized just how much that post was depending on prior knowledge.  I have spent many years studying chemical engineering with a focus on biomolecules, and as such I am fairly well versed in a wide variety of scientific principles.  However, I recognize that this is a writing blog that is intended to appeal to those who, while they may know way more than me about the nuances of English and have probably read more literature than I ever will, might not have had as much time to spend dabbling in the sciences.  I decided to write a series about biology in science fiction that would be useful for a wider variety of writers than just (biologically focused) scientists and engineers.

Because of my occupation, I’ve had to sit through enough lectures, classes, and readings on biology and chemistry that I cringe at bad representations.  As a Christian who grew up in a strictly fundamentalist household, I also understand people’s trepidation with the theory of evolution and gene manipulation.  I hope that in this implementation of the Biology in Science Fiction series, I will be able to spark ideas on how to deal with the potential conflict of interest to write good science fiction while still wrestling with the moral and religious implications.

First, though, let’s deal with what genes are, how modifications work, and what that means in science fiction.

What is DNA?

Crystal structure of DNA.*

DNA is a molecule – a really, really long molecule that’s made up of smaller parts, or groups of atoms called nucleic acids.  These acids stick together to form the now-famous double helical structure, and they do so in a sequence that is specific to the organism it comes from.  This means that your DNA forms a shape that no one else in the world has, a shape that scientists and (if we’re being quite optimistic) crime investigators can figure out.

DNA is present in every cell in your body.  Within this cell, what it does is act as an instruction book to tell them what to do.  Because everyone has slightly different genes, their bodies do slightly different things.  This is why some people are really tall, some are short, some are more naturally athletic, and some are more naturally bookish.  Don’t discount experiences, though!  DNA controls more of your ‘maximum potential’ than it does your actual performance, in most cases, and as such education, practice, and other experiences determine a lot of who a person is.

What has DNA?

Crime shows and the dramatization of DNA as the signature of human individuality have taught many people that humans contain DNA, but there’s a lot of misinformation out there that has led us down some rabbit holes.  I once met someone, and thus believe there are probably a lot more someones, who hadn’t realized that everything living, many things that are dead, and some things that are questionably living** all naturally contain DNA.

DNA isn’t exclusively a human molecule.  Your dog has DNA, your corn has DNA, bacteria have DNA, your kale has DNA – even your coffee beans and tea leaves have DNA somewhere in there.  And, what’s even cooler, is that the DNA has always been there.  Scientists didn’t put DNA in animals and plants.  DNA is an organic molecule and naturally occurs in all living creatures.

You may also remember I said things that are questionably living.  Many viruses contain DNA, and they are in some ways the original DNA modifiers.  Not considered alive because they require a host cell to transmit and copy their own DNA sequences* to their ‘offspring,’ viruses insert their DNA into a host cell and insert their own sequences into the host.  When you feel sick, it’s your body responding to your cells being forced to make more viruses.***

But what about GMO’s and Non-Natural DNA?

GMO’s, or Genetically Modified Organisms, are life forms that have had their DNA modified by humans.  When most people think about GMO’s, they’re thinking about an artificial piece of DNA injected to an organism that will change how it functions.  Artificial DNA is the exact same molecule as the naturally occurring DNA, but the sequence of amino acids is chosen to perform a specific task.  This is how we get plants with genes to make them resistant to pesticides, how we can make apples that are resistant to browning, amidst a lot of other potential benefits.  There are lots of debates over whether these plants (humans haven’t really**** gotten around to GMO animals yet) are safe for human consumption, but unless you’re writing some form of propaganda-esque story, the truth behind that isn’t relevant to this post.

Arctic Apples are a really interesting GMO example in which you can see big results from a tiny change!*****

I’ve manipulated non-natural DNA and put it into a whole bunch of E. coli as well as strains of bacillus, chinese hamster ovary cells, S. cerevisiae (yeast), viruses, and probably other things for briefer stints.  I haven’t done plants yet, but holy moly do I want to operate a gene gun one day (which only works with plants).  I’ve only ever done up to three genes at a time, and the more genes that need to be expressed, the more difficult it is to modify the organism.  It’s also extremely difficult to modify an entire metabolic pathway, or set of actions a cell takes – whatever product you’re trying to make is probably not beneficial to the organism’s reproduction, so there’s always competition between making the cell produce what they want and making the cell keep itself alive.

In order to perform better gene manipulation in humans, a greater understanding of what the thousands of molecules in our bodies do is required.  We only understand a fraction of our genes, and the amount of non-expressed DNA is immense and still not well comprehended.  To have a really tight, scientific approach to gene manipulation in a story, deep understanding of how certain genes and their prescribed proteins act would be really nice.  Even without having the luxury of a known gene with known product and function, appreciation of the molecular actions that translate into larger effects (or phenotypes) is a key part to maintaining scientific accuracy in the modern era.

Humans are a long, long ways off from programming superpowers in someone or something.  Superpowers may be impossible, given that someone capable of superpowers may require more food than would be reasonable.  That being said, cures for genetic ailments such as sickle cell anemia are probably on the horizon – at least for newborns.  If large-scale gene modification using artificially introduced DNA is in your story, it’s probably going to need to take place in the far future.  Even then, the question of what kinds of powers are introduced becomes intriguing, since the bounds of what it means to be human becomes blurred.

One movie I thought did an excellent job concerning near future genetic modification was GATTACA.  It was mostly focused on the ethics of the practice, but it had relatively scientific methods and thinking behind it.  When I think about science fiction that includes good genetic premises and ideas, this is up there as a gold standard.

Modern Examples of Massive Scale Gene Modification

I was surprised when I learned that most people, including you, probably have a great example of the most pervasive form of genetic manipulation living with you in your house.  I’m talking about your dog or cat.

Pictured: genetic disaster.

Humans, long before they even knew about what DNA or the other biological molecules were, figured out that you can breed animals that express certain traits with other animals of the same species to continue focusing in on that trait.  What they were doing, without true comprehension, was making dogs and cats that had certain DNA sequences that told the animal’s cells to perform a specific task – and it’s desperately effective.  This method of DNA modification has massively increased our crop output, been responsible for the shape of modern chickens, and brought us monstrosities such as… well, specific dog breeds that I shouldn’t mention lest I get an army coming after me (*cough* pugs *cough*).

Eugenics as a method of genetic modification would probably work.  It’s frightening, ethically unsound, and questionably effective given the amount of time required between human generations (and, thus, changing societal goals could alter the implementation), but the concept is actually… scientifically sound.  A book that wants to show the horrors of gene modification need not have even a single piece of scientist-made DNA.

Some Notes From Throughout

*Molecular graphics and analyses were performed with the UCSF Chimera package. Chimera is developed by the Resource for Biocomputing, Visualization, and Informatics at the University of California, San Francisco (supported by NIGMS P41-GM103311). The crystal structure provided is B-form DNA, PDB file 1BNA.  To learn more about Chimera, which is my favorite crystal structure viewing and image export program, you can go to the Chimera homepage or read some scientific papers about it.

**Some viruses don’t contain DNA!  Instead, these viruses will contain RNA, a similar molecule that has different functionalities.

***The immune response is amazing.  We even use our own immune molecules as medicines.

****There are CRISPR modified animals in existence, but as of this writing they are mosaics – not all of their cells contain the modification.  As well, these organisms have not had targeted gene manipulation with specific results.  There are knockout strains of mice out there, which means strains of mice that do not express a particular gene or do not have it, as well as mice with modified immune systems and expression of human genes, but these are expensive and almost entirely for scientific purposes.

*****Image was taken from the Arctic Apples information page.  These apples do not readily brown because they do not contain the enzyme that helps browning occur.  In principle, keeping apples crisp and fresh helps reduce the need for preservatives in pre-sliced apple products.  I suggest looking at their page here.

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