00:03
In order to answer this question, let's talk about inheritance.
00:06
A woman and a man are both heterocygous for a disease, for a girl, genetic disease.
00:10
So they are heterocycles like this, both of them.
00:15
Okay? and it says, if they have one child, what is the probability that he or she will be affected? so you have this cross, endless makeup and a square here.
00:32
Homocycle dominant, heterozygos, heterozygos, and homocybozygos.
00:36
Recessive, okay? so you have a total of four possibilities.
00:40
Out of these four possibilities, only one is going to be affected because this is the homo -the -ho -recessive that is that caused for disease in an autosomal recessive inheritance pattern disease.
00:52
So the answer here is going to be one out of four or one quarter.
00:57
So this is the answer for the first part of this question.
01:00
Then it says, if they have two children, what is the probability that at least one of them will be affected.
01:06
So if they have two children, what is a chance that at least one of them is affected? so the probability for at least one, let's see again the equation, it says the probability that at least one of them will be affected.
01:22
The probability for at least one affected is equal to the one minus the probability of all not affected.
01:42
Okay? so what is the probability that all of them are not going to be affected? if you have two children, what are the chances that both of them are not affected? so here you have a total of three possibilities.
01:54
In one of those, i'm sorry, a total of four possibilities...