I’ve read that for animals, say, a cloned mammal the DNA of the original host is the same used for the clone, so it’s already aged and degraded from time. I grow many plants, and so I regularly make clones via cuttings and divisions. So I wonder why the new individuals can have the same vigor as it’s parent plant? Does DNA not degrade in plants? I’ve also read that inbreeding can occur in plants. On a side note, about the super massive tree structure Pando, that Aspen forest from only like 1 tree I think. It’s estimated to be 80,000 years old and is technically a single individual, as every stem (tree) comes from the same roots and has the same DNA. Meaning at some point a long time ago a single seed made 1 tree which eventually became a forest occupying over 100 acres. How does DNA replicate so many times over in plants with no issues? Is it because the differences between plant and animal cells? I don’t know a lot about these things, just a random thought I had. Any explanation would be appreciated 🙂
In: Biology
I don’t have an exact answer for you on this, but I hope this will shed some light.
Many plants exhibit what is called [polyploidy](https://en.wikipedia.org/wiki/Polyploidy), where they have extra sets of chromosomes. Cells generally have 2 sets of chromosomes, but plants get a little funny and will sometimes have extras.
For *brassicas* (like mustard, broccoli, cabbage, kale…), there’s a theory called the [Triangle of U](https://en.wikipedia.org/wiki/Triangle_of_U) where related species with different numbers of chromosome pairs would make seeds with polyploidy that would then incorporate the pairs into its genome and become a diploid set again.
Point is plant DNA is a little more malleable than animal DNA.
Still though, that piece of the plant that you pulled and cultivated is still the same plant. Some plants are just like that where they can grow if you put part of it in the ground, as long as you have a node (the places where branches grow from) present. The nodes contain plant stem cells such that they can differentiate into roots if underground. With tomato plants, you can let them grow for a little bit and then lay it horizontally under the soil with the top still above the soil, and those nodes will start growing roots and creating stems. Same plant too.
I’m sure my response will get deleted but from what I recall, animal dna is exactly like you described. The dna is essentially a time stamp.
You can take dna from a human at 30 years old, clone it, and the clone will ‘start’ at 30. It won’t grow from a baby into what is now that person. It will just grow from a clump of cells into what is exactly that person, albeit without memories, experiences etc.
Plants are different in that an oak can live for hundreds of years for example. I don’t know if a study has been done to see if ‘cloning’ or taking a stem from a plant and creating a new one has any side effects on the new plant.
plants can already clone themselves without any help. most plant parts contain at least some meristematic cells with all of the information needed to make a copy of the original plant. plants don’t exclusively clone themselves in the wild because it’s not evolutionary advantageous.
cloning a mammal on the other hand, involves removing the nucleus from an egg and replacing it with the nucleus of a donor cell. it’s something mammals don’t do outside of a lab & the process is kinda error prone and so a lot of those embryos don’t make it.
other than that, mammal clones have similar lifespans to their non-cloned counterparts:
https://www.sciencedaily.com/releases/2013/03/130307122958.htm
Plants are in general evolutionarily closer to having duplication as a legitimate reproduction strategy. Some plants straight up reproduce by sending out suckers and growing new plants from them, and those plants can be easily and simply divided.
It’s not impossible to fix damage caused to DNA by replication, it simply isn’t done in animals, because dying off to make room for a new generation with new combinations of genes and mutations means that a species is more adaptible to changing environments and can therefore migrate faster and survive disasters better than a species that can’t. Typically adaptability isn’t a strong selector for species that don’t move with simple environmental concerns, which means purposeful die off is a waste of resources.
Importantly telemere damage doesn’t occur for some types of stem cells, otherwise all species would eventually die off. The same process just happens longer in an individuals life in plants.
This works with lots of animals too, just not the ones that you are thinking about.
If you cut off a chunk of coral you can grow a new coral head from it, and in fact this is a common way for corals to spread in the wild (hurricanes or something breaks off a bit, it grows in a new spot). Some of the corals are thousands of years old.
There are other coral relatives that work this way, plus many worm species where if the worm breaks in half both halves can regenerate. Starfish can also reproduce this way. Probably some other invertebrate animals I am not thinking of. Many animal species that work this way just don’t seem to really age much at all.
Mammals and other vertebrates tend to have lots of controls on how much their cells can divide because it’s easy for them to be killed by cancer…lots of complicated plumbing for cancer to muck up, and cells that are mobile and can move around. But plants (and coral, and many other invertebrates) don’t have to be so worried about controlling their cell division because cancer isn’t able to kill them as easily (in plants, particularly, any cell dividing out of control can’t migrate to other parts of the plant). Furthermore, because their body structures are such that they _can_ reproduce by fragmentation, it makes sense for them to take advantage of that by not putting an “age limit” on their cells the way humans and many mammals do. You can’t just chop an arm off a human and regrow a new human from it, because an arm doesn’t contain enough of the body to be able to have everything it needs to regenerate. But half a worm would. Or a branch of a plant. Or part of a starfish. So it’s not really generic “DNA degradation” caused by environmental problems that is the main issue with cloning. It’s inbuilt DNA regulation that is hard to wipe away. Although plant “cloning” also has the benefit of you chopping off a whole branch with a bunch of cells. If one cell is messed up it just wont thrive and the others will take up the slack. Cloning from a single cell, like they do in mammals, means if that one cell has a problem the whole organism will have it.
Anyway, the DNA in these animals gets mutations just like in anything else (this is a seperate phenomenon from the inbuilt limits to replication you see in mammals that cause issues when cloning…and other issues which are due to epigenetic markers on the DNA). But mutation is a random process. Some cells might get hit by a bad mutation, others not. The unhealthy ones will die, the others will keep going…just like some offspring might be born with genetic diseases and die while others would be fine (remember, DNA in eggs and sperm is just like other DNA, it also gets mutations).
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