Chapter 21, Problem 15P

A gene has two alleles A (frequency = p) and a (frequency = q). If a population is at Hardy-Weinberg equilibrium, develop mathematical expressions in terms of p and q that predict the following mating frequencies:

a.	Between two AA homozygotes
b.	Between two aa homozygotes
c.	Between two Aa heterozygotes
d.	Between an AA homozygote and an aa homozygote
e.	Between an AA homozyote and an Aa heterozygote
f.	Between an aa homozygote and an Aa heterozygote
	Considering your answers to parts (a)–(f):
g.	Do the six possibilities listed account for all possible matings? How would you know whether this is true mathematically? Demonstrate this latter point by setting p equal to an arbitrary number between 0 and 1 such as 0.2.
h.	Can you develop a simple, general rule for calculating the mating frequencies between individuals of the same genotype versus the mating frequencies between individuals of different genotypes?
i.	If the population is equally divided between males and females, what proportion of all matings will be between an AA male and an AA female? Between an AA male and an Aa female? Between an AA male and an aa female?