Cells and microorganisms are already so small, that I find it hard to imagine how someone can be looking through a microscope with tiny scissors or something cutting DNA or RNA from the nucleus of a cell. Also they are able to cut specific genes from those strands of DNA/RNA. How do they even read the genes. Also then how do they extract it out the cell and then insert it in another, or set it aside etc.
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The way it’s is shown in presentations and the vocabulary used (“cut”) does make one think the scientist uses litttle siccors. But it is very far from that.
It has been answered here already but I thought I’d clarify a bit. The mechanisms we use come from bacteria and viral mechanism for changing around DNA or breaking it down. Nothing has been specifically developed it’s just been discovered and we use it to our advantage.
Cut: as mentioned before there are things called restriction enzymes and restriction cut-sites. A specific restriction enzyme will sever the DNA at a certain sequence (cut -site). these sequences, when cut, produce mirrored ends that can then be matched back up. So it follows that If you cut two peices of DNA with the same cut sequence, they can be matched together and a recombinent DNA sequence can be formed.
Amplify: use PCR, which is essentially the process every organism uses to copy it’s DNA but at a higher temperature and many many times. This gives us a large quantity of DNA so we can measure it, or extract it, and we’re more statistically likely to get the desired DNA from it.
Transformation: this step is a bit more complicated but like the others it uses the methods already present in organism, just to our advantage.
There are things called plasmids which are circular peices of DNA and are essential used to transfer DNA from bacteria to bacteria , it’s a method they use to evolve. These plasmids can be inserted in a bacteria or a yeast cell and be read by it.
We use the cuting step to create a plasmid with the DNA we want on it. Just by matching cut sites. Amplify it using PCR to make a lot of it. And then insert it in the cells(mix it all together in a vial ). Insertion is yet again done using mechanism already present in the organism and not by anything fancy (usually). You can use a virus that will enter the cell. You can shock the cell and make it think it’s dying (at which point it will suck up neighbouring DNA fragments in an effort to “evolve”).
A “new” method is CRISPR that is more targeted and can be done on cells that can’t read plasmids(human cells). It’s a “programmable ” cut site maker essentially. Again, a mechanism discovered in an organism, not engineered.
Edit: how to read the DNA.
DNA is made of two strands. When it’s copied it seperates and each strand is used as a template to make new DNAs one nucleotide at a time in order.
To read and determine the sequence of DNA. you essentially make it copy (PCR) but with nucleotides that are both radiolabeled and will force the reaction to stop. You end up with a bunch of DNA strands of every possible length that terminates with a radiolabeled nucleotide. So now you now the position and the specific nucleotide.
(You can separate DNA by size using gels and electricity ).
I think there’s a very efficient way to do this that uses the same base concepts but is all automated and fast
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