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Current time:0:00Total duration:9:15

Video transcript

say my mom has blue eyes and my dad has brown eyes what color would my eyes be now for a long time people thought that the color of my eyes would just be a mix of the color of my parents so it would be a mix of blue and brown so I'm kind of a dark brownish blueish eyes and that's what they believed for every single trade so for example my mom has straight hair and dad has let's say curly hair then again they believed I would get a mix of them kind of straight kind of curly wavy hair and so for a long time people thought this is how traits get passed or inherited from parents to children it'll just be a mix the traits will just be a mix in the children but is this really how traits gets passed on who's going to answer this question well there was one man actually a monk named Gregor Mendel who decided he's going to answer this by growing a lot of people ants in his garden now if you're wondering why he chose pea plants then we've talked a lot about this in a previous video talking about how people ants have a lot of characters to experiment with and how these characters have only a couple of trades and all of that so if you need a refresher I'll be a great idea to go back and watch that video on which is called why Mendel chose pea plants okay but if you feel you're cool with this then let's go ahead and see what kind of experiments Mendel performed on these pea plants so Mendel performed a lot of experiments on different characters right so let me take one example the character height so what he would do in one of his experiments is he would take a pure tall pea plant and then cross fertilize it with a pure short peopleand and then see what offspring that they would give now I'm pretty sure you may be wondering what do you mean by pure plants what is this pure mean pure basically means if you were to self pauline so if you were to self pollinate a tall plant it should give all tall plants if you self pollinate a short plant it should give all short plants and what do you mean by self pollination well suppose this is one of the flowers of the tall plant then what I mean my self pollination is you take the you take the what do you call this a pollen grains yeah you take the pollen grains from the flower and put it back into the carpel of the same flower basically you put it back into the female reproductive part of that same flower and then it'll grow seeds and then you saw those seeds and then if you find that all the seeds grow into tall plants then that then we will say this is a pure tall plant this is the meaning of pure and similarly if you were to do the same thing for the short man as well so you take one of the flowers of that short plant and then you self pollinate meaning you take the pollen grains put it back into the same flower let it fertilize and then you grow seeds and you saw them and if you find all of them grow into short plants not a single tall plant but all of them grow into short lands then we will call this a pure short plant okay so Mendel prepared these pure breeds for his experiment a pure tall plant and a pure short plant let me get rid of these now and so for his experiment you know what he does he cross pollinated them meaning he takes the pollen grains from one of the plants and he puts it into the flower of the other and you can take it from anyone to anyone so for example he might take the pollen grains of flower from at the tall plant and then put it into the car pail or the this part of the short plant so let's say he cross fertilizes them like this and then this will start growing seeds then he solves that seeds to see what we will get after this cross fertilization so what do you think we will get well let's get rid of the flowers and make some space so what do you think we end up with well I would expect to get some medium height plants right because you have a short one you have all Joshua you have a tall one you have a short one so maybe they get mixed and you end up with all medium-sized plans that's reasonable to think right but to Mendel surprise and to even my surprise when I learned this we get all tall plants what that's right big shock hundred percent of them hundred percent of them end up being tall this raised many questions what happens to the short one does it have no effect at all why aren't we getting any medium sized plants why aren't we getting any short plants what is going on anyways he addressed these plants as f1 generation plant this is the name that he used them and if you are wondering why he called them f1 the word the F stands for a Latin word fill y'all I hope I'm pronouncing that right it means son or daughter okay so that's why these plants are called f1 generation first generation sons our daughters of these you can say but yeah Mendel was shocked by this so he didn't stop over here he started asking questions one of the main question he was asking is are these plants these tall plants the same as the parent tall plant are this same they look the same because they have the same height but are they really the same is this also a pure tall plant that's the question he tried asking and to answer that question you know what I did he did another experiment he didn't stop over here when he does next what it does next is he takes one of the f1 generation plant which is basically tall he takes one of the f1 generation plant this is f1 generation oops let me use this white color so this is f1 generation and he self-pollinate sit self-pollinate sit to see what we get so again it'll grow seeds and then he saws that seeds what do you think we'll end up with well surprise surprise now some short plants are found another shocking thing to see right because again where did these short plans come now from certainly right and guess what mentally when counted them so in this f2 generation is the second generation sons and daughters or offsprings what when he counted them you know what he got he found that there were roughly three times as much tall as you had compared to short so the tall to short ratio was 3 is to 1 and if you're wondering yes he also cross-pollinated the f1 generation plans and he gets exactly the same result 3 2 1 and you know why this number is so important because it's not random it turns out he gets the same answer for all the characteristics that he experiments with I mean for example when he takes when he takes the color of the flower into consideration again he takes a pure purple colored or pea plant and crosses it with a pure white pea plant in the first generation you know what he gets a similar result this time he gets all all purple colored flower no yellow or no white flowers at all but then when it takes one of these f1 generation purple flower and self pollinates guess what he gets he now gets three times as much purple as white white comes back it's in minority some small amount three to one ratio but it comes back with the same ratio 3 to 1 so what's going on why don't we see the white flower over here but somehow it comes back in the next generation what is going on before we think of what's really going on one thing is very sure our initial assumption that traits get mixed and sent to their children is absolutely wrong isn't it I mean if that was the case we would have found some medium plants over here or over here we would have found some pinkish color flower mix of purple and white but we don't get that so Mendel from his experiments conclusively proved that traits do not get mixed at all that in itself was a huge discovery but now had to figure out what it all meant and I'm gonna leave you here hanging with this question as Mendel must have been left hanging with we will look at the exciting conclusion of what all this means in the future videos meanwhile ponder on this for a while see if you can come up with any theory to explain this