To answer the question titling this section and the module, let’s start by asking what you need to know. Then let’s figure out how you can get that information. To do this, review the question, the information provided in previous sections and develop a table similar to that below.
Table 1
What do I need to know to answer this question? 
How do I get this information? 








Check your outline above by working through the example below.
Review Figure 1. Imagine that these parents mate randomly. What genotypes could their offspring exhibit? Put another way, what allele combinations could we see in the offspring generation if every parent has an equal chance of reproducing and thus contributing an allele to the next generation?
Since two alleles exist for this locus in this population, A and a, three possible genotypes can occur in the offspring of these parents. These three genotypes are:
Recall that the last can form in two ways: Aa or aA.
Calculate how frequently we expect to observe each possible genotype identified in problem 1. Please show your work. Refer to the outline you developed or reread the preceding sections for guidance.
The frequency with which a genotype will occur in the offspring generation is equal to the multiplicative product of the frequency with which each allele comprising the genotype appears in the parent generation.
Counting the buckets depicted in Figure 1 above reveals that the A allele occurs with a frequency equal to 15 out of 20 or 0.75 and the a with a frequency equal to 5 out of 20 or 0.25 in the parental generation. Consequently,
 the AA genotype will occur with a frequency equal to 0.75 x 0.75 = 0.5625 in the offspring generation.
 the aa genotype will occur with a frequency equal to 0.25 x 0.25 = 0.0625 in the offspring generation.
 the Aa genotype will occur with a frequency equal to (0.75 x 0.25) x 2 = 0.375 in the offspring generation.
Now check your work: have you identified every possible genotype that could appear in the offspring generation when each parent has an equal chance of reproducing in the population above?
To do this, consider the following: if we have identified every possible genotype, then the frequencies calculated in question 2 will sum to 1 (i.e. 100%) because we will have accounted for 100% of the genotypes that could possibly occur in the offspring if all parents have an equal chance of reproducing and contributing alleles to the next generation.
Check your work. Have you omitted any possible offspring genotypes? How do you know? Please explain.
We have not omitted any possible genotypes because the expected genotype frequencies (0.5625 + 0.0625 + 0.375) sum to 1 as expected if we have accounted for every possible genotype that could occur in the offspring generation of a randomly mating, parental generation with these allele frequencies.
If you have missed a genotype, what one do you think you have missed? Why?
If you missed one genotype, it was probably a heterozygote, either Aa or aA. Review the information found here to understand the likely source of your error.
If you have missed one, correct your response to question 2 above. Now you should have an accurate description of the offspring genotype frequencies that will materialize when every parent has an equal chance of reproducing in this population.
Finally, we are ready to address the question heading this module, are offspring generation genotype frequencies necessarily expected to be the same as parental generation genotype frequencies when every parent has an equal chance of surviving and reproducing? Please explain using your results to support your conclusion.
No, parental and offspring generation genotype frequencies will not necessarily be the same in a population that is not evolving. Our data support this conclusion because in the parental generation above, the AA, aa, and Aa genotypes occur with frequencies equal to 5 out of 10 or 0.5, 0 out of 10 or 0.0 and 5 out of 10 or 0.5, respectively. Whereas, if these parents mate randomly, the AA, aa, and Aa genotypes will occur in their offspring with frequencies equal to 0.5625, 0.0625 and 0.375 respectively.
How confident are you that parental genotypes are not necessarily recreated in the offspring generation when every parent has an equal probability of surviving and reproducing? Please explain.
Any response in which you discuss elements about which you are confused or describe your understanding is acceptable.
Now let’s confirm that random reproduction produces the offspring genotypes we predicted based on the parental allele frequencies above. To do so, we will run a simulation in which the computer will randomly pick 50 pairs of alleles to represent 50 random fertilization events.
Are the genotype frequencies in the offspring generation produced by the simulation the same as those you predicted? Yes or no? Please explain.
Yes, they are. The AA, aa, and Aa genotypes occur with frequencies equal to 0.5625, 0.0625 and 0.375 respectively in the offspring generation of the simulation exactly as predicted.
Do the data support the prediction you made about the similarity between parental and offspring genotype frequencies in problem 6 above? Yes or no? Please explain using evidence to support your conclusion.
Best answers describe the prediction you made in problem 6 and how the data from the simulation do or do not support that expectation.
Imagine randomly mating the offspring generation just produced. Would you expect the genotype frequencies of their offspring to differ from their own? Yes or no? Please explain your conclusion and support it with evidence either logical or actual.
The genotypes frequencies should not differ between these two generations. You can support this using data collected from the simulation or by calculating the genotype frequencies one expects to see in their offspring as a result of random mating by these parents. This is illustrated below. F1 refers to the offspring generation just produced and F2 refers to their offspring.
To calculate F2 genotype frequencies, the first pieces of information we need are the allele frequencies of their parent's generation, F1.
We know that the allele frequencies of the F1 generation are identical to those of their parent's generation because every parent had an equal likelihood of surviving and mating (i.e. they were not subject to an agent of evolution). Consequently, in the F1 generation
 A occurs with a frequency of 0.75
 a occurs with a frequency of 0.25
Since the same allele frequencies and the same method are used to calculate the genotype frequencies for both the F1 and F2 generations, the genotype frequencies of these two generations must be identical.
To confirm this, review below:
 the AA genotype will occur in the F2 generation with a frequency equal to 0.75 x 0.75 = 0.5625.
 the aa genotype will occur in the F2 generation with a frequency equal to 0.25 x 0.25 = 0.0625.
 the Aa genotype will occur in the F2 generation with a frequency equal to (0.75 x 0.25) x 2 = 0.375.
and these calculations are identical to those we made to calculate the genotype frequencies for the F1 generation in problem 3.
What do the conclusions to problems 9 and 6 suggest about the potential for similarity between parental and offspring generation allele frequencies when a population is not subject to any agents of evolution? Please explain.
In some cases, parental and offspring generation genotype frequencies may be the same and in others they may differ. The results demonstrate that if a parental generation, like F1, is the product of random mating and is itself not subject to any evolutionary pressures then its own genotype frequencies will be replicated in its offspring as observed in F2.
a. Finally, return to the simulation and click the box marked X, run it and record the results. Notice that the parent generation is identical to that in Figure 1. Review the results. Do you think that the offspring generation is the product of random mating? Why or why not? Please explain using data to support your conclusion.
b. What do these results indicate about the similarity between the allele frequencies of the parent and offspring generations? Why? Please explain.
a. The data suggest that the offspring were not the product of random mating because the genotype frequencies observed in the offspring generation differ greatly from those predicted HardyWeinberg and thus when the population is not subject to any agents of evolution.
b. The parent and offspring generations must have different allele frequencies because if they were the same, then the genotype frequencies of the offspring generation would be equal to those calculated by HardyWeinberg.
 frequency  the number of times an event or observation, for example a particular measurement or condition like blue eyes, is observed in a collection of events or observations like those comprising a sample, population or study. In this statistical sense, a frequency is equivalent to a proportion. For example, the frequency of a particular allele is equal to the number of times that allele is observed in a population over the total number of alleles for that locus in the population. Can be expressed as a fraction, a percentage, a decimal, or a probability.
 genetic equilibrium  state of a population in which allele frequencies remain unchanged from one generation to the next.