00:01
In mendel's original work on the genetics of garden peas, he found that yellow seed color is dominant over green seeds and round seed shape is dominant over wrinkled.
00:11
Mendel crossed true breeding homozygous yellow, round, seeded plants with green, wrinkled, seeded plants.
00:19
What are the genotypes of the parents? so our first parent is true breeding, which is another way of saying homozygous, yellow and round.
00:27
Yellow and round are both dominant.
00:32
So therefore, all four alleles are going to be dominant.
00:37
Homozygous dominant.
00:38
Homozygous, meaning same allele.
00:41
The second parent is green and wrinkled.
00:45
And then it tells us that green and wrinkled are both recessive.
00:49
And in order for that recessive trait to show in the phenotype, both alleles have to be recessive.
00:55
There can't be any dominant alleles.
00:57
So that means our second parent is homozygous recessive.
01:02
What are the gametes that can be produced from each parent? so parent number one are homozygous dominant.
01:12
We have a capital y and a capital r.
01:15
And that is because if we show you over here, it's all of the possible allel combinations that you would put into your pennett square.
01:24
So we look at our first y, it matches up to each r.
01:28
And then our second y matches up to each r, making the same dominant y, dominant r.
01:37
And then we could write that four times.
01:44
The second parent gametes, the same thing.
01:47
All are recessive, so you would have all recessive gametes.
01:57
Set up a punnet square to determine the genotype and phenotype that can result from this cross.
02:02
So when you cross a homozygous dominant with a homozygous recessive, all of the children are going to be heterozygous...