 Hi there. I have a question for you. Imagine you take a batsman with amazing batting skills like maybe Dhoni or Tendulkar. Or let's say you take a singer who has a great voice, or maybe you take this guy. You know who this guy is, right? So what's my question, you know? Do you think they will be able to pass on their amazing skills to their kids? I mean think about it. For example, do you think Dhoni or Tendulkar? Might be able to pass on their amazing batting skills to their kids so that they would be maybe born batsman or you know, this singer might be able to pass on her amazing voice skill to her kid. Or maybe this guy, you know who this guy is, maybe he's able to pass on his amazing problem-solving skills to his kid. Do you think they can gain from their parents these skills? I don't know about you, but I feel yeah. I mean, why not? Because we inherit so many things from our parents. We inherit their looks. We inherit sometimes their diseases. I'm going bald and I'm guessing I also inherit that from my parents. So yeah, maybe we can also inherit these amazing qualities as well. Why not? But keeping my feelings aside, what does science have to say about this? Well, let's find out. I think to answer this question, we need to look at what exactly gets passed on from the parents to kids because of which they inherit all that stuff. What exactly it passes on? And we've talked about this. It's the DNA. That's basically what gets passed on. Your DNA is basically an instruction manual that contains information of how to build you. My DNA contains instructions of how to build me. And we get this DNA directly from our parents. And so this means the big question is, do any of these skills, like the batting skills or the thinking skills or maybe the singing skills, do they cause changes in their DNA? That's the big question that we want to answer. Because if they do, then those changes in the DNA can be passed along to us and then we can inherit those amazing abilities. If they cannot change the DNA, then we will not be able to inherit those abilities. So what do you think? Do you think they can, you know, the skills can change their DNA? I'm going to tell you the answer right now itself. No, they cannot. Why not, you ask? Well, let's see. Here is a cell. OK, this is what we are made of. Our body is made of cells. So the DNA is resting inside the nucleus. OK, that's where the DNA lies. Now, let's see what happens when you practice batting skills. When you keep batting for years and years, you know what changes it causes to your body? It might change, you know, you get better at it. You get a better hand to a coordination. So that means your neural muscular, neuromuscular connection becomes stronger. You might get more muscles out of it because you are playing a lot. All those changes are happening outside of the nucleus. That's right. You might gain more mitochondria. Your cytoplasm might become denser. You might have more proteins. But all these changes are happening outside of the nucleus. So none of that is going to change your DNA. The same thing over here as well. For example, when you keep singing for a long time, your voice gets better. Again, the changes are happening outside the nucleus. OK, whatever changes are happening to your voice. This is happening outside the nucleus. Again, no changes in the DNA. And same thing over here. If you start thinking more and you start gaining more knowledge, again, that basically changes the neural structure in the brain. It turns out to be a little complicated. But again, most importantly, no changes in the DNA whatsoever. This means if you are the knowledge that you have gained by years and years of practice cannot change the DNA. You cannot pass along that knowledge to your kids. So the kids will not be able to inherit any of the amazing abilities from their parents. Sounds disappointing, right? But it did not be. It did not be disappointing. And before I talk more, let me just write down what we just spoke. So let me go to a different page. Let's just write down. So we said the traits or the knowledge that you acquire over your lifetime, like your batting skills or maybe your thinking ability. In general, these together are called acquired traits. OK, acquired traits. Makes sense, right? Because you are acquiring them. You didn't inherit them from your father or mother, but you're acquiring them in your lifetime through practice. OK, so acquired traits are basically the traits that you gained, gained over lifetime or lifetime. And what we learned about these acquired traits, we saw that they cause no change. Let me write that down over here. They cause absolutely no change in the DNA, no change in the DNA. And to be to be very specific, what I mean is no change in the DNA of germ cells. Germ cells, germ cells are basically the sperm cells and the egg cells, which are involved in reproduction. And as you might know, it's the sperm that fertilizes the egg and eventually grows into a baby, right? So that's why I'm talking about these germ cells, the sperm and the egg. It causes no changes in the DNA of these cells. Of course, it causes no changes in the DNA of any cell. OK, but more importantly, it does not cause changes in the DNA of the germ cells. And that's the reason why this cannot be. This cannot be inherited. So not inherited, not inherited. And let's also write down what changes they cause in your body. They do cause changes, but what changes do they cause? They cause changes in your non germ cells, right? They cause changes in your non germ cells, which are called somatic cells. Basically the muscle cells or the vocal cells or maybe the cells in your brain, they cause changes in them. That's what we call the somatic cells, so non germ cells. OK, non germ cells. That's where the changes happen. Again, not the DNA, but outside the nucleus. All the changes happen. So does this make sense now? If it does, great, because let's see if you got this. I have a couple of interesting scenarios for you now. In the first case, consider a couple of monkeys who are in a relationship before they make a baby, they decide to cut off their tails. Maybe they didn't like their tails or whatever. Now the question is, do you think their baby or at least one of their babies would be born without a tail? What do you think? All right, what do you think? This might sound reasonable, but think about it. Cutting off their tails has no effect on the DNA of their germ cells, of their sperm and egg cells, right? No changes in the DNA. If there is no change in the DNA, there will be absolutely no reason why their kid should have no tail over there. So their kid will be born with a tail. Cutting their tail off has no effect on their baby. OK, another one. Here's the theory of how giraffes evolved that long neck. So the theory is, long time back, giraffes' ancestors had short necks and they wanted to eat food from these tall trees. So they started stretching their neck. Because of their continued stretching, their babies were born with a little longer neck and they did the same thing. They also kept stretching their necks over and over again. And after a few generations, finally, we have giraffes born with very long necks so that they can eat food. That's how giraffes evolved. What do you think about this theory? Do you agree with this? All right, let's see. So when the first ancestral giraffes, they started stretching their necks. Do you think that caused any changes in the DNA of their germ cells? The sperms and the eggs? I don't think so. At the max, this must have given it a next brain, right? So if they did not cause a change in the DNA, there is no reason to think why its kids should get a longer neck. Why would they be born with a longer neck? It makes no sense, right? So if you think about it, this cannot be true and it isn't. This is wrong. But it seems so logical, right? I mean, I always thought this is how giraffes evolved. But that's not how they did. And of course, if you're wondering, then how did giraffes involve these long necks? Remember, the DNA changes did happen, but they happened randomly. OK, the random mutation caused this effect to happen. And you can go back and check the videos on natural selection when we talk about this in more detail. So hopefully now you have a clear understanding of why acquired traits cannot be inherited. And I just want to end by saying, at first, this might sound disappointing that you cannot pass down your acquired traits to your kids. But think of it this way. This means Dhandulkar or Dhoni was not a born batsman. Einstein was not a born genius. And singers are not born singers, which is good because this means even you and I can master all of these skills and even more with practice and patience and become as good as the best talents in the world today. And that's why at Khan Academy, we believe that you can truly learn anything. Have a good one.