Video Gallery

Introduction to genetics and heredity

Go to Video Gallery Added Mar 03, 2015 •

Copy this URL:
Embed code:	<iframe class="edlio-embed-player" type="text/html" width="640" height="360" src="//www.khswaveriders.org/apps/embed/?v=74657" frameborder="0" allowfullscreen></iframe> Change dimensions

Go HD

Show Transcript

hello boys and girls welcome to tonight's vodcast on genetics and heredity now genetics is the study of how traits are inherited through the inter the structures called alleles which will talk about in a little bit however heredity the big idea behind genetics is the passing of traits from parent to offspring so here we have a celebrity couple Brad Pitt's the dad in Angelina Jolie is the mom and here's our daughter Shiloh jolie-pitt from a couple years ago look at their daughter you'll know something otters in nice mix of characteristics from both parents so if you take a look at their daughter's eye structure she obviously gets it from her dad Brad if you take a look at the height of her forehead she gets the height of her forehead more from her mom then she does her dad if you take a look at her lips and her mouth area you'll know set that's a cop sure both parents the shape of the lips come from Brad Pitt where is the fullness of the lips comes from her mom the reason why Shiloh jolie-pitt looks like this is because she is herded these characteristics from each parent her heredity is mixed because she inherited different alleles from her parents which is the same reason why every turn off looks like a combination of their parents so take a look at what alleles are first of all wheels are different forms or versions of a trait which are controlled by the genes the same time alleles are different forms or versions of a gene so as we've seen this before in our DNA chapter genes are the instructions to make proteins and their just sections do you know so we take a look at the upper right hand corner here in this dotted line box this section of DNA is a particular Gene nauser stated before have different versions and they are called alleles as we know genes and what they do or solely based on the orders of the adenine guanine Simon's Insider within that section of DNA for example here we can have a gene to make brown eye color based on the order of bases in this picture however someone is blue color the order of those adenine guanine Siamese inside of scenes would be different so the illegals are different because the base pairs are different orders for the different so sick of look at some examples of what alleles are ice cream but differences in the recipes call for different flavor as we take a look here each one of these flavors like the fish food in the chunky monkey and the chocolate fudge brownie and Cherry Garcia those could be a wheels for ice cream they are all ice cream however there different versions of that same kind of ice cream in the same goes for human characteristics except we don't count scream is characteristics we have different characteristics so the gene to make eye color everyone has a gene to make some sort of eye color however people do have different eye colors some people have the blue eye Leo which is the gene that makes blue eyes other people have brown oil which is the gene to produce brown eyes however hair color can have different alleles too so we all genes to make hair color however not everyone has the same so for example there is no legal or Gene to make blonde play Taylor Swift has or jeans make brown hair like third baseman for the New York Mets David Wright has so again Wheels just these different versions to make these particular traits we all have the ability to make these traits but we just have different colors and different versions of them so let's about how is all discovered so the idea of inheritance in the passing of traits from parent to offspring began of this man Gregor Mendel and use the first one default rates through several generations of Offspring in use mathematics and use probability to prove it so what do you like to study was obviously plans cuz he was a gardener that worked in a monastery and one of his favorite plants to study was a pea plant and the pea plant was a good plant to study because I'd many different traits to it such as Peapod for seed shape or plants height or flower color and so forth so we can study all these different characteristics well what we going to talk about tonight experiment on Peapod color so Gregor Mendel took two different color peapods we had green pea pods and we have yellow peapods and then you Paul painted on which means you took the pollen from one of the pods and then fertilize the eggs or the other one so for example we could say he took the pain from the green pea pod and put it on the yellow pea pod flower to see what would happen now most of us would probably think that if we took a green colored organism and made it it with a yellow colored organ is in the Oscar will be some sort of a mix between green and yellow however we're Gregor Mendel found in his first generation when he watched the Peapod develop from the first Offspring group he knows that all The Offspring were green there was no yellow color it was all green color so you got the wandering well what happened to the green color was it destroyed did it go away so what are you ended up doing was he took to those peapods in the first generation and then cross them and fertilize them and in the second generation he noticed out of every four Offspring you'll get three green pea pods and then one yellow Peapod so sick a look at how this works before we move on there certain phrases that you need to know in order to understand what's going on when we talk about genetics it's like learning a brand new language to the first thing you need to know what a dominant allele is a dominant allele is a gene or an allele that covers another Gene allele so for example green color was the dominant allele in our example with the peapods and when we write out a dominant allele we always use it as a capital letter it's always written as a little so the green color would be expressed as a capital G  a recessive allele is a trait or the allele that gets covered by the dominant allele so the yellow trait in this experiment was a recessive allele because it was covered in the first generation but then showed back up in the second generation and they're always Nest lower case letters and if you notice we just use one set of letters we use capital G for green and then we use lower case G not my butt lower case G for yellow in the other two words that you should know are pure breeds and hybrids  trees are organisms stop to the same alleles or either two dominant alleles or two recessive alleles pure-breeds Always written as are the two capital letters where to lower case letters and then we ever hybrids hybrids are organisms that have two different alleles one dominant and one recessive so they're the opposite as we write out a hybrid Gene combination will see a mix of a capital G in a lowercase G if you think a hybrid car you'll know that hybrid car has two different fuel sources it has an electric fuel source and after it reaches a certain speed it'll kick into a gas source so since there's two different fuel sources it's called the hybrid well here we have two different alleles cap a dominant allele and a recessive allele king of hybrid Offspring look at his experiments here so again that means they were either too or sets of genes or two dominant genes being that the yellow turn out to be recessive we would write the yellow as lowercase G lowercase G turn the pure green was turn out to be dominant was written as capital g capital G now we use this tool call the Punnett Square here in the Punnett Square helps us figure the probability of what types of Trades are going to show up in The Offspring to put in squares always have four squares in them and each Square represents an offspring that will be made so you set this up what you do is this you take a parent and you put their Gene type or genotype at the top here so since we have two boxes here and I put the Green Parrot up here I'm going to use capital g capital G so I put one capital G over the box and then the other Capel G over the other box and then I took the yellow pee and I put their jeans next to certain boxes so I have lower case G here and lowercase G there so each box has a letter over or next to it that's what we'll do is fill out the letters into each box dominant allele I'm going to bring into this box and then recessive yellow will I'm going to bring in that box whenever you get a dominant and a recessive loyal pair together the dominant or capital is always written first it's never the other way around that's an incorrect way to write it same exact way dominant allele green recessive allele yellow dominant allele green sepolia yellow  and the dominant allele for green and recessive allele for yellow  this is where you need to send the rules of dominant and recessive whenever you take a look at the genes in an offspring if there's ever a dominant gene paired up with a recessive gene the dominant gene is always going to show so since in this Cross or in this mating pair the dominant gene is green which is shown by the go to letter this Offspring is going to be green  and since every other Offspring has a capital G in it for green every Offspring is going to be green so as a result Mendel found as we said that all this plants are green whenever you cross to purebred plants together you're going to get whatever the dominant trait is so let's take a look and see what happens in the second generation to give us the result so we talk earlier so as we said Mendel took to The Offspring from the first generation and cross them or made them so that the eggs are fertilized and each plant was a hybrid plant saw on the previous cross this plans are going to be big G little G this plants is going to be big G Little J  civil set up are Punnett squares just like we did before one parent on the top one parent on the side and each letter over a box and then now we're going to fill out the Punnett Square down the capital G and capital G  bring over capital G and bring down the lower case G  bring down the LG bring over the lowercase G and this last box going to bring down our lowercase G and bring over our lower case G so if you go by a rules of dominant and recessive again anything with a capital G the dominant trait is going to be shown so green is dominant so every pod that has a capital G will get a dominant color so this has two dominant traits in it so it's going to be green  this Offspring here one dominant trait in it but still dominant so it's going to show Green as well as this one however if we take a look at the fourth Offspring will know said there is no. good trait there it's two recessive alleles so the two recessive alleles will Express themselves in this pea pod will be yellow  so as Mendel found that when he crossed two hybrids he got three dominant plants which were the green plants and then one recessive plant which was the yellow so here's a summary what Mendel discovered sowa Mendel discovered after his two crosses was this  some traits when present cover up other traits and those be the dominant ones so every offspring that has a dominant and recessive  always showed the dumb color however the hidden traits are there sesat rates on Gone Forever they're still present in all The Offspring here except for this one but they're not phone but when you pair up the two recessive traits together they didn't Express that recessive trait  so that's how you felt a Punnett Square boys and and that's how the idea of alleles and heredity works so we're like for you to do now is going to the back of your note packet and fill out the practice point of squares thank you

Uploaded by D. Henriques.

Video Gallery

Introduction to genetics and heredity

Popular Videos