00:01
We have a population in hardy -weinberg equilibrium.
00:03
A gene has two alleles, and we've got 80 % of the dominant, 20 % of the recessive.
00:11
So let's have p is the dominant, and that's going to be 0 .8.
00:15
Q is the recessive, that's going to be 0 .2.
00:18
Now, i've used these because these are what you commonly see for hardy -weinberg, although you could use any label for them.
00:25
Which percentage of the population would be heterozygous? okay, so there are three possible gene types.
00:32
An individual could have two of the dominant.
00:36
They could have one of each, heterozygous, which is what we're looking for.
00:40
Or they could have two of the recessive.
00:44
As we work it out, well, we're going to write out the heidi weinberg equations.
00:49
So one of them is p plus q equals one, which you can see is true, and it makes sense.
00:54
This is the allele frequency.
00:56
Every copy of the gene is one of these two alleles, so they're going to to add up to 100%.
01:01
The second looks like this.
01:05
So it's got p squared plus 2pq plus q squared, and this also equals 1...