The Possibilities of Man-Altered DNA
What was once thought to be a sci-fi movie script is coming to life. DNA alteration might hold a key to becoming superhuman.
What is DNA in the first place? I remember my thrill when I first realized that every living being on Earth, literally every organism, has a certain body code that determines the looks and functions of that being. That code is composed of differently arranged organic compounds.
There are just four basic molecules (also called DNA letters, A, T, C, and G namely) that DNA is made of. Such a chemical arrangement makes it possible to build a thread of virtually any length, made of molecular “knots”, the sequences of which form genes.
Say, four knots make it possible to build 16 different gene combinations. The length of a human DNA is 6 billion knots which might imply that the number of possible DNA combinations is thus some astronomical number that won't fit into a single line. Because there are different DNA lengths in nature, the diversity is almost endless.
The length of each knot is 0.34 nm so a full uncoiled human DNA thread would be more than 2 meters long.
Everything about you is packed into that gene mess. Some parts of a DNA carry little to no information as some researchers claim but some other parts clearly define the color of your skin and your eyes, the shape of your fingers – everything. Some particular genes make you prone to certain diseases. Some genes, on the other hand, make you immune. Genes responsible for life span are thought to exist, too, and scientists dream about finding a gene of immortality.
Expanding the DNA vocabulary
If DNA alphabet is comprised of only four letters, what would it be like if it contained as many letters as English alphabet? The similar question is applicable to English alphabet itself: wouldn't that be quiet restrictive is there were only four letters?
So a group of researchers at the University of British Columbia and the National Institutes of Health decided to look for a pair of molecules that would soundly fit into DNA just like ATCG do. In 20 years of research, they indeed found two suitable compounds among thousands of them and called these two X and Y. This was done to expand the language of nature and see if it could bring up richer stories, or speaking scientifically, produce new proteins with new functions. Since then the DNA alphabet became ACTGXY.
The practical motivation to expand the DNA language is to see if semi-synthetic organisms can manufacture unique proteins that potentially can be used as drugs to treat various diseases. Insulin is one such story, a protein. Synthesizing it or any other protein is very hard in a lab environment so there's an alternative to make an organism that synthesizes it.
Proteins are composed of amino acids. Because an organism with expanded DNA would possibly be able to produce proteins of different sets of amino acids, the output of various new proteins would hopefully have something of interest: a new remedy, perhaps.
One of the desirable functions of such proteins is the ability to distinguish a certain type of cells inside a human body and target them and nothing else, cancer cells, for example. It would be great if drugs made with the help of this research could last longer as they usually break into simpler compounds or get digested one way or another pretty fast.
This research has been a collection of desires, hopes, and expectations until, in 2014, the first-ever organism with six DNA letters was created. It looks like some ordinary bacteria, no demonic grin on its face at least.
X and Y letters are built with elements that are not what is often encountered in nature so bacteria with these letters won't survive outside a lab for long. And they don't eat natural food, so they won't be able to spread uncontrollably. There's a dream to make one such bacteria that would eat up all the plastic in the oceans, break it into harmless organic compounds and then starve to death on its own and die out completely.
In 2017 a population of semi-synthetic bacteria that glow green was created. They synthesize jellyfish luminescent proteins except that this protein has XY insertions.
The ambition is to start experimenting with larger organisms and eventually humans to adjust their properties and functions.
A breakthrough or an atrocity
There are some mechanical operations that can be done with normal human DNA and have nothing to do with bacteria. One way is to rip a DNA thread apart by laser and insert a needed fragment in place of an extracted one. As we said, this is done to replace some genes of weakness and vulnerability. Another way is to chemically break a sequence. The result is just the same.
He Jiankui, the researcher of Southern University of Science and Technology in Shenzhen claims he altered human embryos with an intention to increase their resilience to HIV. The news broke out in November, 2018.
These embryos were healthy so a DNA amendment was not necessary.
He was immediately vilified for unethical actions.
In my opinion, as long as the decision to alter embryos was parents', not He's, no one can judge about its ethics even the so-called ethics professors. There's a modern liberal opinion about the legalization of abortions, and that every woman is free to decide what to do with her body. No one has the right to jump in with their moral suggestions that are purely subjective.
The operation was consensual.
Think, if evolution is a random process of mutations that are only tested by time then human-induced evolution with a goal of strengthening an organism in mind is nothing bad. If it doesn't turn out well, it doesn't always turn out well in nature either. That at least would provide an invaluable experience to researchers.
Hats off to He.
Yes, there's a risk of cancer as a result of such an operation. There's also a risk make a DNA more resilient to dangerous and rare genetic diseases and increase the overall adaptability of an organism.
The age of synthetic organisms is here. The age of rewriting our own DNA is here.
What comes in the next year or two?