[Music] good day Learners Welcome to our new lesson in our previous discussion we talk about some of the non-mendelian genetics such as incomplete dominance co-dominance and multiple alleles incomplete dominance is a form of inheritance in which the dominant trait is not completely dominant over the other allele and the resulting phenotype is intermediate meanwhile in co-dominance both alleles are expressed equally in the phenotype of the head they recycle which means both traits are observed or expressed in the phenotype on the other hand multiple alleles are the traits controlled by a single Gene with more than two alleles for today's lesson we are going to talk about another non-mendelian genetics most humans have 46 chromosomes 22 pairs of autosomes or somatic chromosomes and one pair of sex chromosomes sex chromosomes control whether the organism will be male or female males have 44 autosomes plus XY sex chromosomes while female have 44 autosomes plus XX sex chromosomes both males and females have 22 pairs of autosomal chromosomes an affair of sex chromosomes a male offspring will be produced when an egg is fertilized by a sperm carrying a Y chromosomes similarly a female Offspring will be result of a fertilized egg to a sperm carrying an X chromosome therefore there is a 50 probability of having male and female Offspring not all traits are controlled by alleles found in autosomes there are traits governed by the sex chromosomes and these traits are called The Sex sling traits sex-linked traits are recessive traits these are the traits that are found on either one of the sex chromosomes sex-link traits affect both males and females but in some cases one particular sex is more prone to have a sex literary a sex-linked trait is a trait genetically determined by an allele located on the sex chromosome a rate that is determined by the allele on the X chromosomes is particularly described as the x-linked traits whereas the traits that determined by the allele on the Y chromosomes is said to be the y-elect traits an example of excellent traits is color blindness and hemophilia on the other hand an example of wyling traits is hypertrichosis which is characterized by hairy ears these traits is exclusive only to meals now let's talk about the genetic table of colorblind color blindness is the inability of a person to distinguish colors especially green a person will be colorblind if he or she inherit recessive genes from parrots now let's take a look at the genotypes and phenotypes of female this one is for the normal female and this one for the carrier female that means she has a normal vision because Sex Link traits are recessive genes and it can be masked by the other healthy X chromosomes therefore since she is a carrier she will have the hidden traits of being colorblind which can be passed to her Offspring and this one is for color blind female a female can have colorblind Vision if both X chromosomes carry the colorblind traits now let's take a look at the genotypes and phenotypes of male this one is for the normal meal and this one is for the color blind me now as you can see males are easily affected by the x-link trees because they only have one copy of X chromosomes and ones that one copy of X chromosomes carries x-link trace the male will have sex linked disorder let's have an example Aina having a normal vision married a man who is a color blind what will be the genotype and phenotype of their offspring and how many percent of their offspring will have a colorblind Vision now we're going to solve it using the Punnett Square remember our first step is to determine the genotypes of the parents and based on the problem the parents are normal females and color blind males now this is the genotype of a normal female and this one is for the color blind me now let us solve it using the Punnett Square once done we're going to summarize the results write down the genotype and the phenotypes of The Offspring now this is our genotype we have to carrier female and two normal male and the genotypic ratio is 2 is the two for the phenotype we have 50 carrier female and 50 normal meal now another example of excellent traits in human is hemophilia a person suffering from hemophilia could die from loss of blood even from a small wound because the blood either clots very slow or does not clot at all now let's take a look at the genotypic table or the genetic table of Hemophilia this one is for the normal female this is the carrier female it means she has the hidden traits of Hemophilia which can be passed to her offspring this is for hemophilic females since both eggs carry hemophilic trees now let's take a look at the genotypes and phenotypes of a male this is for normal meal and this one is for hemophilic meal now as I mentioned a while ago males are prone to sex sling traits because males have only one X chromosomes and once it is affected they will have the disorder now let's have sample problem 2. hemophilic carrier female married a normal meal what will be the genotypes and phenotypes of their offspring and how many percent of their offspring will have hemophilia the first step is to determine the genotypes of the parents and based on the problem the parents are hemophilic carrier female and a normal male now this is the genotype for hemophilic Carrier female and a normal male now we're going to solve it using Punnett Square once done we're going to summarize the result write down the genotypes and phenotypes of new obstring now this is the genotype of The Offspring we have one normal female one carrier female one normal male and one hemophilic meal and this is the genotypic ratio we have one S21 is to one is to one and the phenotype is 25 normal female 25 carrier female 25 normal male and 25 hemophilic meal now let's talk about sex influence trees sex influence traits or autosomal traits that are influenced by the sex chromosomes it is also a recessive traits one of the example of sex influence trait is baldness and is influenced by the hormone testosterone and since males have a higher level of testosterone compared to females if a male has one recessive allele he will show that trait but it will take more assessment for the female to show the Savory now let's take a look at the genetic table of baldness here we're going to represent baldness as a small letter B since it is a recessive traits now this is for the genotypes and phenotypes of female as you can see for the female to become bald it needs two recessive genes of bulb now let us compare it to male as you can see males only need one recessive gene of baldness to become bald that is because baldness is influenced by the hormone testosterone which is men produce higher amounts compared to women now let's have sample problem number three a heterozygous not bad female married a homozygous bald man what will be the genotypes and phenotypes of their offspring and how many percent of their offspring will be bald first we're going to determine the genotypes of the parents and based on the problem the parents are heterozygous not bald and a homozygous bald man the genotype of the heterozygous not bald female is this one why because when we say hetero that means different this genotype has two different genes just look at the symbol the other one has a capital letter B while the other one has a small letter B the small letter B carries the gene for baldness this genotype is considered not bugged because baldness is recessive gene which means it is a hidden tree now the genotype for homozygous mold is this one why because hormone means the same and this genotype carries the same genes in which the same small letter b and small B indicates baldness now let us solve it using Punnett Square once done we're going to summarize the result by writing the zero type and phenotypes of The Offspring now let's talk about sex limited traits sex-limited traits are those traits limited to only one sex lactation is a good example of sex limited trait that is exclusively among females however cattle carries Gene for lactation in both males and females lactating Gene is a dominant gene over non-lactating recessive gene and female cattle carrying one dominant gene or two dominant genes lactation will be shown nevertheless neither male cattle having the dominant genes nor male cattle that have recessive genes will update so that's it see you in our next lesson and if you are new to my Channel please don't forget to hit the Subscribe button and hit the Bell notification so that you will be notified for more videos like this