00:01
So in this question, we have a woman who has with normal vision.
00:08
So in this question, we have a woman who has normal vision.
00:13
And she has a son.
00:17
And we know that this woman's maternal grandfather, so her mom's dad.
00:29
This person right here, the maternal grandfather, is colorblind.
00:35
And we want to know the probability that this person, this son right here, is colorblind.
00:42
Colorblind, the father's normal.
00:46
So we know that colorblindness is an x chromosome.
00:50
So a normal x, this is a normal.
00:55
And i'm just going to put a little dash.
00:57
That is colorblind.
01:01
Okay, we've got our alleles assigned here.
01:03
So this grandfather up here has a colorblind x and a y.
01:15
Well, the mom's going to give a normal x over here.
01:19
The grandfather or the father will give the colorblind x and we're going to end up with this person having a heterozygous genotype.
01:31
So we need to know the chance.
01:35
We're going to call this the mother.
01:37
The chance that the mother is the carrier and we need to know the chance that the son is colorblind, right? and we need to know both.
02:02
Both of those together.
02:05
So let's look at the chance that the mother's colorblind.
02:18
Well, we know that the mother's mother is heterozygous, and we know that the father is normal...