00:01
What is the genotypic ratio of the offspring? we have four options here, a, b, c and d.
00:08
How do we work this out? okay, so we've been given the punnitz square, and we can see that this is a cross between two heterozygotes.
00:17
So they have one copy of a dominant allele and one of the recessive.
00:21
And when you construct a punnette square, you have the parental alleles on the outside.
00:26
So that's what we see.
00:28
We have one parent's alleles, and the other.
00:31
The parents out here.
00:32
You see one, dominant, one recessive.
00:36
The four squares represent combining those.
00:41
So you combine, this one gets a dominant from this parent and a dominant from this parent, this one gets a dominant from this parent, and a recessive from this one, this one, dominant from this parent, recessive from this one, and this bottom right corner gets a recessive from each.
01:01
So that's how this square has been constructed.
01:04
And each square shows the genotype of the offspring...