00:01
In order to answer this question, let's talk about inheritance.
00:04
And this is a pedigree that this question is talking about.
00:07
And it says a three -generation pedigree for a particular human trade is in the following figure.
00:13
You have here one generation, second generation, and third generation.
00:17
Question is, what is the mechanism of inheritance for the trade? now, first, is this pedigree or is the inheritance pattern here auto -so -domin dominant? it means either ex -link dominant or autosomal dominant.
00:31
And the answer is no.
00:32
Why? remember that if a person is affected, then it means that that person has the mutant allele.
00:38
And if that person has a mutant allele, then it means that that mutant allele was inherited from either from the mother or the father.
00:45
So in this case, if this woman here has a mutant allele, then it means that the mutant allele was given by either the mother or the father.
00:53
So one of them has a disease.
00:55
And in dominant diseases, it is enough to have one allele, one mutant allele to develop the disease.
01:00
So if one of them has a disease, then it means that that person or that parent should have the disease too.
01:06
But in this case, they are not affected.
01:08
It means that this is not dominant.
01:10
Okay, so this is not a dominant disease.
01:14
Now, it is a glyceive disorder.
01:16
It is an aggressive disorder because in this case, similar to what we said, this woman has a mutinalil.
01:22
So it means that this mutinalil came from either the mother or the father or maybe both of them.
01:28
So it means that at least one of them has.
01:30
That mutate an allele and it means that they are cagers and you find caggers in recessive disorders because in recessive disorders you need two alleles in order to cause disease.
01:42
Now is this pedigrip from an ex -ling recessive and the answer is no because if it is an excellent recessive then this woman would be like this.
01:53
So most are you right and as i told you before a person inherits one allele from each parent.
01:59
So in this case one way says if an allel should come from the mother and the mother can be heterozygos.
02:06
It means a caviar and hence don't show the disease.
02:10
But in case of the man, he only has one x alil because males are xy, right? they don't have two x alil.
02:18
So in this case, this second allele should come from the father.
02:22
So the father should be like this.
02:23
But this genotype is for a man with a disease.
02:27
So as this man does not have a disease, negative means that this is not.
02:31
An excellent recessive disorder.
02:33
And hence it is an autosomal recessive disorder.
02:36
Where this woman is homozyg excessive and both parents are heterocybozygos, because they are healthy and as they need to transmit, one decisively each of them in order to produce a homozygoseous excessive, then both of them are heterocygous.
02:51
So this is autosomal recessive.
02:55
Then it says, which persons in the pedigree are known to be heterocygous for the trade? so in this case, we know that this to parents here are heterocygles.
03:04
Remember that in this case the homocygous dominant and the heterocygous are normal and the homozygous residual is for a disease, a person with a disease.
03:15
In this case, both parents need to have a obsessive adil, so they can be heterocygose or homocyglysm.
03:22
But as both of them are not affected, they mean that they are heterocycles.
03:26
Okay.
03:27
Now, in this case, we are not sure about a genotype for this father here.
03:35
But we know that the three daughters here, all of them are heterocybous.
03:40
Why? well, because this mother only has recessive adil to transmit to these three daughters.
03:46
So it means that these three daughters are going to have at least one recessive coming from the mother.
03:51
So they can be heterozygous or homozygoseous or homozygous.
03:53
But as they are not shaded circles, it means that they don't have the disease, but they are heterocygous, okay? in this case, the same this woman has a disease so it means that both parents if they are healthy both of them are heterocyte like this okay and we don't know the genotype for for these two off -pring here because they can be homozygous dominion or heterocygios because from a cross between two heterocygios let's make a panel square here if you want you have homozygoyles heterocygos, heterocygous, and homocygous and gaseous.
04:32
So, as you can see here, these two offspring here from this cross can be either homozygos dominant or heterozygos, okay? the next question says, what is the probability that 3 -2 is a cagger? it means this woman, this daughter here.
04:46
So you already know that this daughter is not affected.
04:50
So it means here you have a total of four possibilities, but you're not going to consider this one here because you already know that this woman cannot be homo -sigital gaseous, because she does not have a disease, right? so it means out of three possibilities, this one, two, and three, you are not considering this...