00:01
Okay, we are looking at snapdragon flowers where there's two different loco that will determine what the flowers look like.
00:08
You can have one locus that says it'll be either large or small.
00:11
Another locus that says the flowers will be either red or cream in color.
00:16
Now, we have two parents that will cross.
00:21
This first one has small red flowers.
00:25
It's homozygous for both of those alleles.
00:27
And the second one has large cream flowers.
00:30
And again, homozygous for both alleles.
00:34
When you do that cross, all of the f1 generation ends up being the same, and this is why.
00:45
Well, they have to get one l allele from the first parent, and in either case, it'll be a lowercase l, and they have to get one l allele from the other parent.
00:57
And in either case, it's a capital l.
01:00
So you've got to have those two in the f1 generation, and the same thing with the r, alleles.
01:06
Have to get a capital from the first parent, have to get a lowercase from the second parent.
01:11
So we know that all of the f1 generation has this genotype of heterozygous for both alleles.
01:20
Now, we're told that we're going to take one of these f1 plants and cross it with a totally different snapdragon plant that is homozygous recessive for both alleles.
01:37
And then we're given information about the f2 generation, but we also want to know about the chai squared test.
01:48
So we're going to do that.
01:50
And in order to do that, we have to know expected ratios for all of the phenotypes...