00:01
You had several questions about blood types.
00:03
So i'm going to roll through them, and i'm going to show you some examples and show you how to approach these different types of questions.
00:09
So first off, we're going to look at the information that's given.
00:12
We are told that you could have a few different blood types, and we're going to look at multiple different things here.
00:17
So if a and b are both dominant alleles for blood types, so if you have at least one allele for a, you'll have type a, blood.
00:32
If you have at least one for b, you'll have type b blood.
00:35
But because they're both dominant and they're sort of co -dominant, if you have one a and one b, you'll actually have type a -b blood.
00:46
But if you have neither of those, if you have the recessive, just plain eyes, then you'll have type o blood.
00:53
And then you could be rh positive if you have at least one dominant r -h -alele.
01:00
And if you do not have any dominant alleles, you'll be rh negative.
01:06
And then the l -m -n -n locus is pretty self -explanatory.
01:13
They are co -dominate.
01:14
So if you have two amyles, you'll present with type m.
01:17
If you have two ns, it's type n.
01:19
And again, codominance, if you have one of each, you'll have l -m -n.
01:30
You have a series of questions where you are given a cross and you're told you're asked what type of phenotypes and genotypes could you receive from that cross.
01:45
So i'm going to do the first one to show you what is expected and how to do that.
01:50
So this is the cross that we're doing.
01:53
In order to do it, you need to make a 4x4 cross because it's going to be a die hybrid cross.
02:00
Then we're going to look at all of the possible allele combinations you could get from either parent.
02:05
So for this first parent, we could have the first allele with the first r allele.
02:11
So you could get a and r.
02:16
You could get the first allele with the second r allele, a and lowercase r, that little i allele with the first r allele or the little i allele with the second r allele.
02:32
And so you'll do that same process with the second person, all of the possible combinations.
02:39
And then you would just complete the cross as normal.
02:50
Once you complete it, you can see that it's a fairly simple cross because one of our people had the same blood type alleles and the same r's alleles.
03:01
So then you can break it down and find all of the different phenotypes, whether they're a positive, a minus b positive, b negative, a b positive, a, b negative.
03:15
So you can see in this first column, it is all ab, and then they have one dominant r -h allel, so they are ab -positive, so there's four of those.
03:27
In the second column, they're all the same again.
03:30
And you see ab, but no dominant r, so they're all ab -negative.
03:36
Next column, again, they're all the same.
03:39
Like i said, this is an easy cross.
03:40
So they're b, there's no a, but they do have positive, so they're four b positives.
03:50
And this next one, they're all b, but they don't have the positive, so they are b negative...