Concepts in Genetics | Biology

Concepts in Genetics | Biology


Welcome to this beautiful lesson of introduction to genetics. Yes in this lesson we’ll be taking a look at the terms or the terminologies which we usually referred to in genetics. That is we’ll be taking a look at a few concepts so that the chapters ahead the Mendelian genetics non-Mendelian genetics or molecule bio anything that we study. Yes we need to know a few terms in genetics and that’s the reason why we dedicate this first and the second lesson towards knowing the few concepts or knowing the few terms in genetics. So right now we will be focusing on what we need to know about genetics. What are the terms, what are the concepts everything that we need to know in case of genetics. Yes let’s try focusing on all of them one by one. Well basically usually become across a huge green tree having beautiful amount of leaves and then it is completely heavily loaded with sweet and very bulky fruits and beautiful flowers at times. Yes it’s one single tree having beautiful flowers, beautiful fruits and the green lavishing leaves that we find. Yes genetics is similar to that tree. Yes we can refer to genetics and that beautiful tree. Because genetics has beautiful flowers it has amazing fruits on top of it, it has green lavishing leaves. That means there are so many concepts which are precursor to the other one. There are so many concepts which are useful for photosynthesis. That means which are useful for carrying out certain important activities. And that’s the reason why we can refer to genetics as a very beautiful tree having all these components which make up the complete constitution. And that’s the reason why today we begin with knowing a few important terms in genetics. What we need to know in genetics part one is this lesson where we take a few times and in the next lesson we’ll be talking about the other terms with respect to genetics. So let’s begin with knowing a few terms in case of genetics a few important terms or concepts. Yes the first one is genetics itself. Yes what exactly is genetics. Then we talk about the concept of genes. We need to know about alleles. We need to know what exactly is the concept of characters. What exactly is the concept of traits. Yes after this we need to know after all these concepts we need to know something called as dominant gene. Then yes after dominant we have recessive. We need to know about dominant and recessive. We need to know about homozygous and yes heterozygous. Then we need to know about the concept of locus. What exactly is locus or singular is loci. Then we talk about the concept of genome and lastly we will be focusing on the concept of gene pool. Yes we’ll be taking a look at all of these concepts one by one. Yes so for understanding this let’s take the help of two reference chromosomes. Yes we take the help of two homologous chromosomes in a diploid individual like you and me and then we study on these concepts. So for example say this is one chromosome from mom yes and this would be another chromosome from dad. Yes now keeping these two as a reference point let’s try studying about these interesting concepts. Now when we say genetics yes what exactly does genetics mean? Genetics is nothing but in simplest words study of genes. Yes we’ll be taking a look at all these definitions in short not the proper official authentic definitions that we need to write exams. We are looking at these terms with respect to our understanding. We need to understand these terms to learn about genetics. Yes so when we say study of genes so what does genes exactly mean? Genes are nothing but those units which are responsible for heredity in the organism. Units of heredity. Yes this is more of a technical definition when we say genes are the segments of DNA which carry genetic information. Yes responsible for heredity. What am I trying to say with this? With this i’m trying to say small segments in the chromosomes. Yes small segments which will be passed from parents to the offsprings as a result of which the offsprings that means the kids the child which is born is having all the characteristics taken from the parents. Yes since it is having two chromosomes since the child has one chromosome from mom and one from dad that means it is going to have a blend or maybe it is going to have characteristic which is expressed from either of the chromosome. Yes so genes are nothing but small segments in your chromosomes the parts of your chromosomes which may carry genetic information. So not what do we mean by alleles? Are genes and alleles the same? Ideally yes. Technically also yes. Genes and alleles are almost the same thing that we try to refer. So what exactly is the difference? When i say genes I’m trying to refer small segments maybe over here and here on these chromosomes. When I take one gene at a time i can refer to this gene as allele. That means out of the two, one gene that i’m talking about is nothing but allele. So to the taken differently one from here and one from here will become different alleles. Right? Another concept another important concept if out of these two genes Yes, if one of this one of this gets mutated that means it gets changed. There is some kind of radiation which is bombarded, there is some kind of chemical change, there is some kind of you know mechanical injuries anything that happens to this chromosome and this particular gene in this area that gets disrupted that gets changed that gets muted. What will happen? That will be the alternative form of this one. It will be the modified form of this gene. Correct? That alternative form of gene is nothing but the allele. Yes can i say a alternative form of a gene. Yes alternative or a different form of the gene will be my allele. Yes one one particular gene at a time can also be called allele. And the alternative form the mutated form can also be called as the allele. So now what do we exactly mean by the term character? Yes what exactly this character represents? Well when we say character yes we are trying to refer to as the name says character means we are trying to refer to the characteristic feature of the particular organism. Yes that means are we trying to talk about the physical, emotional, mental appearances and all? Yes, we are trying to learn about the features Yes, the features or or simply the characteristics of the particular individual of the particular species or the particular organism. So what exactly could be trait? Yes what exactly will be trait? If character is a feature what exactly is a trait? Trait is nothing but the form of character which is expressed in the particular organism. Yes form of character which which is expressed in the particular organism. So for an example for an example say if I talk about character Yes, may be may be we can say height is a character. And if i talk about trait then may be tallest and dwarfness are the traits. So this is nothing but the character which is expressed or character which is possessed by the particular individual organism. Whereas character is nothing but the characteristic feature of that particular organism. So so maybe I can say height, Yes, color of eyes, Yes, eye color, say hair color all these can be termed as a part of character. So what could be trait? The trait for the character height could be tall or dwarf Correct? The trait for eye color can be black eyes, Yes blue eyes, anything green eyes that we have. Yes, hair color could be either black or even blonde, correct? All these all these are the traits which you find for that particular character. So hair color height all these things that we find in the individuals are the characters that we find. Yes these characters can be passed from parents to offsprings. But traits nothing but the actual characters which are expressed. So that is nothing but the form of heredity that you get. Heredity is nothing but what you get from your parents. What all the organisms get from the generation behind them. Yes so trait is nothing but the expressed character in you and character is nothing but the feature that you find in the particular organism. Moving ahead moving ahead let’s talk about the other concepts. Yes let’s talk about the further concepts of dominant and recessive, homozygous and heterozygous. Yes before that before that let’s take the example of this gene. Yes imagine there is a gene which is present here. Okay? A gene which is present here. The homologous chromosomes indicates that the gene other gene for it will be present somewhere here, correct? Since these two are homologous it has to be present here. Now these genes are going to represent one type of character or trait that we know correct? So for example say the first one which is height. Yes for example if this is responsible for height this is also going to be responsible for height correct? One from mom one from dad. Now now the condition that is dominant and recessive, dominant and recessive indicates the form of genes which are present. So when you say when you say one gene which is always expressed irrespective of the other yes is the one which is dominant. So you will have gene which is expressed always. Yes, the gene which is dominant it is dominating one. It will not allow the other gene to be expressed. It doesn’t bother what the other gene is. Yes those genes which will express themselves when they are present are the dominant ones. So what could be recessive? Recessive ones are those ones which remain scared. They always remain suppressed in the presence of the dominant one. So these are those which are suppressed genes. Yes these are the ones which are suppressed in nature. Suppressed means they’ll not be expressed when the dominant one is present around them. They will only be expressed if both of them are recessive ones. That means if the condition is this small represent recessive this is what we already know. Yes capital indicates dominant and small small indicates recessive. Yes those with are recessive in nature they will only be expressed when both of them are recessive. What if one dominant is present with them they will not be expressed They will be the suppressed genes. So dominant alleles or dominant genes are those genes which will express themselves in any condition. Yes whatever is present in the next homologous chromosome maybe dominant may be recessive they’ll always express themselves. Whereas recessive one’s are a bit scared. They will try to see if there is a dominant one they don’t express themselves. Yes they will only be expressed when they are both in the recessive state. So now this gets us to the next concept of homozygous or heterozygous. Yes we know we know that term homo means same and the term hetero means different. So what could be this condition? Yes this condition is nothing but we see here. Both of them are T that means both the genes are dominant ones. Here both of them are recessive ones write t. Both dominant or both recessive means the condition called as homozygous. Yes that condition homozygous is that condition where the individual zygotes where the individual person has both the set of genes. same-same set of genes. Yes, but the individual is possessing same set of genes. It is having the same genes together that means that means both of them can either be dominant or both of them will be recessive. What would be heterozygous then? Exactly opposite hetero means different that means that means both the genes both the genes will be different. So here you only find one condition that is one will be dominant and the other will be recessive. Yes the condition the condition like yes T and t will be dominant and recessive. So so here what we can say is the first condition is homozygous wherein you’ll find TT or tt. Yes and the second condition is called heterozygous because both of them are different. T and t That becomes homozygous and heterozygous individual. So now let’s try learning about something called as locus. We know in maths when we say locus that means a point where it is located. Similarly here locus is nothing but the location of the genes on on the particular on the particular chromosome. Correct? The location where the particular chromosome it on on the particular chromosome where the gene is present. So can I say this pink region is the loci or the location of gene responsible for height? Yes so that forms my locus. Locus is nothing but the place. This is a complete chromosome we need to locate by the genes are. So locus is nothing but the point or the location where the particular gene is present on this complete set of chromosomes. Yes location of the gene on one particular chromosome or on both the chromosomes because we’re studying homologus. So the chromosomes is nothing but the location or the locus or simply called as loci. Locus and loci. Yes, then let’s talk about the concept of genome. Yes we know this concept of genome right? We have learned this and lower grades. Genome is nothing but the set of all the chromosomes set off all the chromosomes which we find in the particular individual. That means we have 46 chromosomes in us, 23 pairs. All the 23 pairs together are making of the genome of our body. Yes all the 46 chromosomes why our particular body? Because every individual every individual human being may have 46 chromosomes, yes, they always are 46 and accept the exceptional cases we have 46 chromosomes. But the genes and all of us are different. Locus of all the genes is same. That traits and the characters are different. Yes character or the locus of that will be same. But the trait that means the height actually the color of the eyes the color of hair all these are different. Hence that is genome for one particular organism Yes, set off all the chromosomes which are present in one particular organism. So what could be gene pool? Gene pool is nothing but set of set of the complete genetic makeup. Yes the set of genes across all species across all the species. Means for one particular species for example say humans. Humans have 46 chromosomes. Yes every individual has their own genome. All the humans all the humans having all the set of genes together will make up the gene pool. Yes that means the genes from all the human beings will make up the gene pool. Genome is the complete genetic makeup of one organism and gene pool will represent all the genes which are present in the complete species. Yes we know there are several characters but more than that there are several traits also. Yes height may be one character but tall and dwarf are two different traits. Eye color is one character but the genes or the gene pool will have so many traits in it. You will have black, you will have suppose say blue, you will have green, grey, cat eyes so many different variations that we find right? So all these variations will make up the complete gene pool? What are the possibilities of having the genes will make up your gene pool? Yes this was about the first part of what we need to know in the concepts of genetics. We have seen genetics is the study of all the genes. Genes are nothing but units of hereditary passed from one generation to another. Heredity which is inheritance or which is getting the makeup of the body from your parents that is nothing but heredity. Yes units of heredity those which will pass the information from one generation to the other genes and study of these genes is genetics. Allele are nothing but the alternative forms of these genes. Character is nothing but the characteristic feature of the organism. And what exactly is the character express is nothing but the trait in the organism. Yes dominant and recessive are the forms of genes. The one which is always expressed is dominant the one which is usually supperessed is the one which is recessive. So now what if we have both the dominant or both the recessive forms of genes in the pair of homologous chromosomes? That condition will be called as homozygous. What if we have one dominant one recessive the one which is expressed is always dominant. So even if i have T and t, the child is going to be tall because it is having a character for tallness. Correct? So now now heterozygous is the condition wherein you have one dominant and one recessive. Two different types of alleles which are present in the organism. Locus is nothing but location of the gene on one particular chromosome. Genome is nothing but the complete genetic makeup of the organism and gene pool is nothing but the collection of all the genes across the complete species of that particular organism. With this we come to an end of the first part of concepts that we need to know about genetics. Let’s meet up in the next lesson where we’ll talk a few more interesting concepts in genetics. We talk about few important terms related to Mendelian genetics in the next lesson. Thank you

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(2 Comments)

  • Johnny Kemmer

    nice content bro

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