For a population in Hardy-Weinberg equilibrium,
   genotype  frequencies  can be calculated from allele frequencies using
   Mendelian principles of segregation and simple probability.

   Here  the frequency of the A allele is 0.7, and the frequency of the a
   allele is 0.3.

   The genotype frequencies in the next generation are:
<LI> AA: 0.49
<LI> aa: 0.09
<LI> Aa: 0.21 x 2 = 0.42

   Under  Hardy-Weinberg  equilibrium,  allele  frequencies  in  the next
   generation should remain constant.

   For example, the A allele should be 0.49 + (0.5 x 0.42) = 0.7.