Let’s learn more about DNA!!! #Science #biology #dna #genetics #fyp

All right, so you're having a baby and the doctors do some genetic testing and they find a mutation. How do they predict if that mutation is going to be dangerous? Let's talk about it. So DNA mutations are dangerous because they're basically typos in the instructions to make proteins that your cells need in order to do their jobs, but not all typos are created equal. I've talked before about how DNA is made up of long strings of these four letters, and each group of three subsequent letters is a step in the instructions to build a protein. To each say, add the next amino acid, amino acids being the building blocks of proteins. Different amino acids have different shapes, sizes, and electrical charges, and the order that you add them in is what dictates how that protein will eventually look and function. See this video for more of an explanation on that. Sometimes one of those DNA letters gets tweaked in such a way that the wrong amino acid gets added at that specific point in the instructions, and mutations that cause this kind of substitution are called "missense mutations." And sometimes that's actually kind of okay. So if the mutant instructions say to add an amino acid that has very similar properties to the one that's supposed to be there, sometimes the protein can still work. It's like if the instruction said to add a chair leg instead of a table leg, it might be a little wobbly, but it'll still do the job. But if the instructions say to add a shower curtain instead of a table leg, then you're going to have problems. But even in those cases, you can sometimes design a medicinal molecule that is the right size, shape, and electrical charge to sort of nudge the protein back into the shape that it's supposed to be. Another kind of mutation is called a non-sense mutation, and I have a whole video on those two. Basically these mutations tell the protein building machinery to stop building when the protein is not actually finished, so they're shipping off this half-built crap that isn't going to work. This is especially dangerous because in most cases, you can't design a molecule that will nudge the protein back into shape because half the shape just isn't even there. Frameshift mutations are similarly dangerous. They happen when one or two letters get inserted or deleted from the DNA, so it throws off those three letter clusters. So every step that occurs after that spot is wrong, and the back half of your protein comes out completely hog wild. But still there, it's just made of all the wrong parts, so again, coming up with a single molecule to fix the whole mess is usually not possible. And finally, there are splicing mutations, so when DNA instructions get printed off and shipped over to the protein building machinery, they require a little bit of modification first. One of those modifications is that they have to remove some extra pages called introns. A splicing mutation means that some of those extra pages get left in or some of the essential pages get taken out, and this causes all kinds of havoc that, again, can't necessarily be compensated for with traditional drugs. For DNA, editing comes in. It allows you to just correct the typo at the source, and the cells can start making their own functional protein again. Now, obviously that's easier said than done, but it's already working for diseases like sickle selenemia, and it is changing people's lives for the better.