> Most of human dna is garbage, it doesn't code for anything.
It's not garbage. If you remove it, you won't have a functional human. "Junk" DNA does quite a bit:
Shield from damage, change spatial conformation of DNA in 3D space, change histone wrapping offsets, provide a basis for gene duplication and mutation (which is fertile ground for evolution), etc.
The spatial effects have a nonnegligible impact on gene transcription.
Imagine gutting your PC and throwing just the essential components into a cardboard box and expecting them to work. A better analogy: do the same to an automobile factory, because that's a better proxy for a cell.
> A full 8% of the Human genome is just viruses.
Which have contributed to our evolution. The placenta has been theorized to be of viral origin. The immune system, which in places uses complex gene rearrangement, also benefits from viral genes.
We know from the Fugu (pufferfish) genome that vertebrate genomes can get away with almost no junk. And before people say "well, that's just a fish, not an amazing human", realize that from the larger evolutionary perspective, the difference between a fish and a human is almost nothing. There is no particular reason to imagine that "you won't have a functional human" without the vast majority of junk DNA. Obviously there would be ethical concerns for doing this experiment, but the fact that onions can have huge genomes and fish small ones is pretty good evidence that there is no correlation with the amount of junk and functionality.
An organism can evolve without junk DNA. But to take human genetic code and remove the junk would change transcription that currently expects it. Portions of the DNA that might be wound would be exposed, or vice versa. It impacts DNA repair, transposition, promoter kinetics, etc.
It's a vargus nerve situation. We evolved around our junk DNA. It's a part of our machine.
Some of them, like HIV, encode multiple genes in overlapping sections. If ever there was a case for intelligent design it would be in these viruses, not complex organisms with huge genomes like plants and humans.
Wouldn’t a virus be hard-selected for short, efficient genetic code? They are so tiny that extra base pairs must have an enormous effect on their physical and mechanical condition.
It really depends on the virus. Some like the famous bacteriophages have relatively large DNA genomes and they are the most abundant viruses on Earth. There are also giant viruses with genomes bigger than some bacteria. It's all very strange. This leads people to think these viruses evolved via different mechanisms. Some are likely ancient and have been around since before other life started using DNA while others seem to be more like highly specialised bacteria that have lost their own ability to reproduce (hence rendering them viruses).
I believe the ENCODE project has shown the junk dna hypothesis is not clearly true. A large portion of the genome codes for something, somewhere above 70 percent, even if most of it doesn't create proteins directly.
As an analogy, a piece of well written code often has a lot of extra info not directly tied to its core function, such as logging, error handling, etc. Much could be removed without impacting the core function, but that doesn't mean it is junk code.
So assuming most of this 5x is "junk" (as the article seems to indicate), how much energy/nutrients does it cost an onion plant to keep copying the "extra junk" compared to if it had the same relative amount of "junk" as that of a human?
I imagine not a lot, given that a cell contains a lot more than the DNA itself, but yeah...
> The energy of the photon is used to excite an electron of a pigment. The free energy created is then used to reduce a chain of nearby electron acceptors, which have progressively higher redox-potentials. These electron transfer steps are the initial phase of a series of energy conversion reactions, ultimately resulting in the conversion of the energy of photons to the storage of that energy by the production of chemical bonds.
I dont doubt that plants have more utility for keeping genetic information. Animals also have much more tricks to reduce their need for genetic information. Think of newborn animals often shaking untill their cerebellum develops more and is able to provide smooth motion while balancing against gravity. or birds singing songs to increase transient information. and one of the biggest information breaktrough ofcourse being the written word and now artificial intelligence
An enormous amount of it comes from development, just the physical and chemical interactions of lots of dumb components making a pretty complicated whole.
Nothing special. The genome of mistletoe seems to be about 40 times bigger [1], while lacking something deemed essential for any other mulitcellular organism [2], the ability to produce ATP! [3]
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[ 3.9 ms ] story [ 77.6 ms ] threadIf you want efficiency, there are viruses with only 2 genes. 2. 1 for their shell and one for the enzyme that copies dna...
It's not garbage. If you remove it, you won't have a functional human. "Junk" DNA does quite a bit:
Shield from damage, change spatial conformation of DNA in 3D space, change histone wrapping offsets, provide a basis for gene duplication and mutation (which is fertile ground for evolution), etc.
The spatial effects have a nonnegligible impact on gene transcription.
Imagine gutting your PC and throwing just the essential components into a cardboard box and expecting them to work. A better analogy: do the same to an automobile factory, because that's a better proxy for a cell.
> A full 8% of the Human genome is just viruses.
Which have contributed to our evolution. The placenta has been theorized to be of viral origin. The immune system, which in places uses complex gene rearrangement, also benefits from viral genes.
It's a vargus nerve situation. We evolved around our junk DNA. It's a part of our machine.
As an analogy, a piece of well written code often has a lot of extra info not directly tied to its core function, such as logging, error handling, etc. Much could be removed without impacting the core function, but that doesn't mean it is junk code.
I believe this is theorized to be a product of domestication (domesticated crops often have a higher number of copies than their wild relatives).
I imagine not a lot, given that a cell contains a lot more than the DNA itself, but yeah...
Take self defense for example. Animals will run or fight. An onion will make you cry with chemistry.
Think of any life function you do with movement. There are equivalent function for a tree that doesn't require movement, and they are all chemistry.
Plants do a lot of amazingly sophisticated, almost impossible (photosynthesis!), chemistry to live. More chemistry means they need more genes.
> The energy of the photon is used to excite an electron of a pigment. The free energy created is then used to reduce a chain of nearby electron acceptors, which have progressively higher redox-potentials. These electron transfer steps are the initial phase of a series of energy conversion reactions, ultimately resulting in the conversion of the energy of photons to the storage of that energy by the production of chemical bonds.
https://www.discovermagazine.com/technology/physicists-see-q...
https://en.wikipedia.org/wiki/Chloroplast_DNA
(I'm asking sincerely; obviously there is more to it than just the chloroplast, but that part of it isn't ginormous)
So the amount of static data isn't a full measure of the question of life.
Protein folding, anyone?
https://en.m.wikipedia.org/wiki/Kolmogorov_complexity
[1] https://www.ed.ac.uk/news/2020/mistletoe-under-spotlight-of-...
[2] https://archive.news.indiana.edu/releases/iu/2015/06/mistlet...
[3] https://www.quantamagazine.org/the-mystery-of-mistletoes-mis...
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