Sci-Fi worldbuilding question - seeding a new planet
Hi, I took first year biology and bio-chemistry, so I know a tiny bit about this stuff - just enough to be dangerous :P Well, enough to come up with ideas, but I’m wondering if this idea is a complete eyeroll for someone who knows more, or if it’s plausible.
I’m working on a worldbuilding element of a story where humans have colonized a planet, and the backstory is on the trip to the new planet, which would be long, obviously, generation ship type deal, instead of carrying an ark full of animals and plants, they created one animal species and one plant species to bring with them on the ship, and hid in the DNA of each, the dna of as many species of useful animals and plants as they could cram into a DNA strand as junk DNA for the animal, but so that it could be recovered later, in future generations of this animal and plant, to seed the new planet with animals and plants.
Obviously they have distant future technology, but I’m wondering if it’s implausible due to the amount of DNA that would be being added into a single animal, if there’s a limit to how long the DNA strands could be, or if they could just have extra chromosomes to make more space. And would it be plausible to have a hundred or more sets of animal DNA stored, or would you go “dude, DNA doesn’t work like that.” Assuming I just kind of handwave that of course they took mitochondrial DNA into consideration too. Hello! This is a really neat scenario you have set up here, and I think, quite honestly, only someone with a strong genetics background would question it (and listen, we’re a small crowd, you don’t need to cater to us). I’ll explain why. Cell size is partially determined by how much space the nucleus of the cell needs to take up, which can be influenced by how much DNA is present in the cell. This is one of the tricks used when making genetically modified fruits or vegetables that we want to be larger than their non modified cousins. The usual rule in genetics is “plant don’t care”, so we can do things like prevent proper cell division and double the genome size (making them tetraploid instead of diploid). They are perfectly safe to consume! (We are eating the progeny of those modified plants, not the plants themselves). Their cell structure is quite able to handle the extra size and stretch; the addition of the cell wall and cellulose makes them much more robust than your typical animal cell.However, there’s a big difference between doubling the genome size and trying to add in several other genomes. Let’s get into the size we are talking about: Drosophila (fruit fly): 180 million base pairs Human: 3 billion base pairs Wheat: 17 billion base pairs Pine tree: 23 billion base pairs Listen, I know some pine tree geneticists and they are brave people, venturing into a genome that size. Plant genomes are huge, generally much bigger than their animal counterparts. They are much more flexible in their ability to acquire genes, and much pickier about which ones they let go. Their survival strategy has generally been “go down the gene aisle and scoop everything into a basket just in case I need it later”. Which has worked very well for them, but it means there’s a lot of genetic material to deal with. So we are talking about some big cells now, probably progressing past the physical limitations of the cell. Unfortunately it looks like the case you’ve described here is probably not possible. However! we have lots and lots of different ways of storing genomes that make them a bit more manageable to carry around. Probably the best way is to make a DNA library, which basically involves chopping the genome up and sticking the pieces into things like bacteria or yeast for later sequencing. I’m making a lot of assumptions here about your story and where technology can go, but I’m assuming that if you can get the DNA out of your plant or animal then you can piece it back together out of some bacteria. This is technology that already exists, and is a way that we actually move DNA around for sequencing purposes. I know that this is not the news you wanted to hear, but hopefully I have given you some starting points to build. If not, I would stick with the original idea. It’s a really cool concept, and I would be willing to suspend my genetics knowledge for stuff like that (sorry, that’s horribly prescriptive, but I liked the idea!) Thanks for sending this in!
