H-Weezy Fo-Sheezy

Hardy-Weinberg

The Hardy-Weinberg equation consists of p squared, q squared, p, q, and 2pq. In order to get started, it is important to know that the p+q= 1 and p squared + q squared=1. For clarification, p represents the frequency of the dominant alleles, while q represents the frequency of the recessive alleles. P squared shows the homzygous dominant individuals and q squared shows the homozygous recessive individuals. Lastly, 2pq represents the heterozygotes, which are the individuals who have both dominant and recessive alleles. 

Here's an example of a Hardy-Weinberg problem.

Example: There are 18 percent of homozygous recessive individuals in a population of 1000. Considering the remaining 82 percent consists of individuals with the dominant trait, how many individuals are homozygous dominant, homozygous recessive, and heterozygous?
 

How to solve:

1. Identify what has been given to you. We know that 18 percent of the individuals are homozygous recessive, which is q squared.
2. Take the square root of q squared to solve for q. (round to the nearest hundredth)
3. We know that p+q=1, therefore we can find p by subtracting the value of q from 1.
4. To find p squared, you would square whatever value you get for p.
5. Next, you find 2pq by multiplying the values of p and q together, times 2.
6. Lastly, to find the number of individuals for each genotype, you must multiply the values of q squared, p squared, and 2pq by 1000.

Answers:

q squared= .18
p squared= .34
p= .58
q= .42
2pq= .49

Number of homozygous recessive individuals: 180
Number of homozygous dominant individuals: 340
Number of heterozygous individuals: 490