00:01
All right, so our question, when exposed to bright sunlight, some people involuntarily sneeze.
00:06
It is controlled by a single gene with two alleles, a dominant h or an excessive age.
00:11
A man and woman who sneeze when exposed to bright sunlight are both heterozygous for this trait.
00:16
So we need to draw upon it square and then show the expected genotypes and phenotypes of the children.
00:24
So the parents are both big h little h and they both sneeze.
00:31
So that means anybody, that means sneezing is dominant when you look at the sunlight.
00:40
So the recessive version means you don't sneeze.
00:43
So since both parents are big h, little h, we can put that in our punnets square.
00:49
So we'll do one of the parents and then we'll do the other one.
00:55
Now we fill out our punnets square, making sure we always write the dominant allele first.
01:02
Then we need genotypes and phenotypes.
01:05
So we can do percents for this part.
01:12
So if we look, we have one genotype, which would be big h, big h, and that's one out of four...