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Acquired vs inherited traits

Let's see if acquired traits can be inherited. Created by Mahesh Shenoy.

Video transcript

hi there I have a question for you imagine you take a batsman with amazing batting skills like maybe doning or Tendo gur oh 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 didn't think about it for example do you think Tony Orton duker might be able to pass on their amazing batting skills to their kid 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 being here 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 high 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 okay so what do you think do you think they can you know the skills can change their DNA I'm gonna tell you the answer right now itself no they cannot why not you ask well let's see here is a cell okay this is what we are made of your body is made of our bodies made of cells so the DNA is resting inside the nucleus okay 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 eye 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 okay 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 this turns out to be a little complicated but again most importantly no changes in the DNA whatsoever this means if you're 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 need not be it need 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 ledges right down so we said the traits are 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 okay acquired traits make 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 okay so acquired rates 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 oh 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 there'll be any of any cell okay but more importantly it does not cost you anything DNA of the germ cells and that's the reason why this cannot be this cannot be inherited so not inherited not in heritage and let's also write down what changes they caused 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 okay 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 scenario 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 alright 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 the deer cutting their tail off has no effect on their baby okay another one here's a theory of how giraffes evolved that long neck so the theory is long time back giraffes ancestor had short necks and they wanted to eat food from these tall trees so this one it's stretching their neck because of their continuous 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 these are at stretching their necks do you think that caused any changes in the DNA of their germ cells the sperms in the eggs I don't think so at the max this must have given it an ex brain right so if the did not cause a change in the DNA there is no reason to think why it's 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 evolve that's not how they did and of course if you're wondering then how did deer offs involve these long necks remember the DNA changes did happen but they happened randomly okay 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 can occur or Donnie was not a bond batsman Einstein was not a bond 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