00:02
So for this question, we're going to set up crosses between different types of chickens with different genotypes.
00:07
So i've listed all of the crosses that we're going to do over here on the right hand side.
00:11
So we're just going to dive right into the first one using a die hybrid pannock square.
00:15
So for dihybrid pannock squares, we look at the two copies of the alleles and we basically have to combine them to look at every possible combination for the two different genes that we're interested in.
00:26
So for example, for this first one, we would take this combination.
00:33
And this combination, but also this combination and this combination.
00:39
So that gives us four things that we're going to have to look at on one of our axes for our punnet square.
00:48
Okay, and you might have noticed that i find it a little bit hard to distinguish between big peas and little piece when there aren't any lines here.
00:57
So i just put little dots next to the little piece to make it a little bit easier to sort of distinguish between the two.
01:04
So we're going to go ahead and get started with that punnet square.
01:08
So we have big r, big p is the first possible combination.
01:14
Then big r, little p, big r, big r, big p, big r, big r, little p.
01:24
Okay, and then on the other side of the punitive square, we have little r, big p, little r, little p, little r, little p, little r, little p, little r, little p.
01:37
So we're going to go ahead and write out all of this punnet square, just looking at the combinations of everything that we see here.
01:52
So i am just writing out the genotypes based on the combinations that we have in our dihybrid punit square.
02:33
Okay, now that i have everything written out, we can look at the proportions of phenotypes.
02:38
And so the first phenotype that we're interested in is walnut.
02:41
And so walnut is anything that has both the rows and the p dominant allele.
02:47
And so i'm just going to underline, this has both a capital r and at least one capital p.
02:53
This one does this well.
02:55
So does this, this, this one.
02:58
This one does not, it only has a capital r, so we'll skip that one for now.
03:04
This one has both.
03:05
Again, this one only has a capital r.
03:08
Both, both, both, both, both.
03:15
Okay, so if we count those up, we have one, two, three, four, five, six, seven, eight, nine, ten, eleven, twelve.
03:22
So that's 12 walnut.
03:29
Next we'll look at rows.
03:30
So rose only has the rose ale and the for the pea gene it has both the little peas.
03:38
So this one, this one, this one and this one are all rows.
03:46
So we have four rows.
03:49
Then just to double check, we're going to look for p.
03:52
Obviously all of these ones are filled in, but in this scenario we would have two little rs and at least one big p.
03:57
We don't have any of those, so we have 0p.
04:01
And then the other possibility is that we don't have any big r's or any big p's, and that would give us the single phenotype.
04:08
So we have zero single.
04:12
So for the first cross here, this is the answer that you got.
04:14
This is the answer that i got as well.
04:16
So you can see we have 12 walnut, four rows, 0p, and zero single.
04:21
So that's the first cross we have here.
04:23
But we have several more to go.
04:25
So i am going to erase this one, and we can start on the second one.
04:37
So again, the second cross will be done the exact same way.
04:40
We just have different alleles this time.
04:44
So remember, we want to look at every possible combination of alleles.
04:48
So for this first one, we have little r big p, little r big p, little r big p, little r big p.
05:00
And for the second one we have big r big p big r little p oops little r big p and little r little p so i will write out this cross based on this information remember i'm putting dots next to the little piece because it's sometimes hard to distinguish the little piece from the big piece when there are no lines on the paper okay so we have our cross completely written out so we're going to do the same exact thing as last time.
06:08
I'm going to look for all of the walnut ones.
06:11
So those have at least one big r and at least one big p.
06:14
So we see this one does.
06:16
Yes, yes, yes, yes, yes.
06:22
None of the rest of them do.
06:24
So we have eight walnuts this time...