00:01
We're going to figure out the genetics of a boy where we're told that his parents, the mom, has normal condition.
00:08
And so both of the alleles on her x chromosomes are for normal.
00:14
But then the dad has this certain trait that we're looking at.
00:19
And we'll say that it's a recessive a in this case.
00:22
He has that on his one and only x chromosome.
00:25
And then their child, we're told, has patched.
00:32
Of normal and patches of this trait on his skin.
00:37
But that's because we see an example of non -disjunction in this child because they have two x chromosomes and one y.
00:47
So clearly one of the parents had non -distunction where they gave this child two chromosomes instead of one.
00:56
So what do we expect? well, we're told that this child has patches of normal and patches of this certain trait.
01:06
And because we're told that the mom shows absolutely no signs, that means either the mom is a carrier or this child had to get the recessive allele and x chromosome from dad...
