Reading about basic molecular biology is pretty mind-blowing. As a computer programmer, I would use the phrase “elegant design” to describe how life seems to work. I discovered a lot of things that I didn’t know about and are truly remarkable.
I knew a little bit about the DNA double helix of course. But what I didn’t know was the impact and/or “reason” such a design is elegant. And I knew about base-pairing, but I hadn’t realized it’s all to do with molecule shapes and molecule binding.
In fact, so much molecular biology seems intrinsically linked to shapes and molecule binding. Given a particular shape, a molecule tends to bind to another molecule. And from there, the engines of life run.
And now I have a question. It seems that DNA can be synthesized pretty easily these days, especially if it has less than 5000 kilo-base pairs. I’ve also read that DNA can be injected into an existing cell, and through some process it can take over the existing DNA. So my question is:
Is it possible to synthesize a minimum-viable DNA that can sustain life in controlled situations?
In computer programming, when we want to understand a complex system, we often try to create something small that tests parts of the system. From there, we can be reasonably confident that we understand a larger system. So, could we synthesize a minimum sequence of genes that can allow a single-cell organism to replicate in controlled situations?
Bacteria DNA is reasonably small but even then it has a lot of inter-gene regions which are not needed. It also has introns, which are regions of gene whih are discarded by the cell during messenger RNA creation. So in our minimum viable DNA (MVD), we definitely want to strip out all that junk.
Bacteria is around today for good reason. It has a LOT of redundancy to survive through the ages. For example, bacteria can get energy from multiple sugars: lactose, glucose, fructose. However, each of those requires multiple genes. In our “controlled environment”, we could easily give the cell a single food source, say glucose which I think is the preferred food source. We can then strip out all the DNA related to the other food sources in keeping with our goal of minimum-viable DNA. Sure our cell may not survive in the wild, but it could survive indefinitely in a petri dish laded with glucose.
So what would the minimum viable DNA need? Well, I guess it would need all the genes that code for replication and for energy absorption. It could work couldn’t it?
Viruses may come to mind. They have very very few genes after all. However, they can’t replicate on their own, and they need many of the genes of the host cell to survive. Our MVD needs to survive on its own. No parasites please!
Of course, it would be okay for the petri dish to have amino acids lying around. I think life itself needed amino acids in the beginning to get “kick started”.
The beauty of the minimum viable DNA would then be that it would be possible for a student to completely understand every single gene (assuming the number was reasonably small). And we could put the entire workings of the gene in a 3D computer model that could be analyzed and understood. And there you have it: Life. Created.