Question

Question 3: Explain why the fixation time of a beneficial, recessive allele is often much longer than that of a beneficial, dominant allele. (2 points)

Question 4: Name two types of natural selection that can maintain polymorphism. (2 points)

Question 5: Consider an annual plant population in an environment with alternating dry and wet years. You observe the dry and wet years are equally frequent. At a locus with two alleles (A₁ and A₂), the relative fitnesses of the three genotypes (A₁A₁, A₁A₂, and A₂A₂) are as follows.

	w11	w12	w22
Dry year	16	0.4	3
Wet year	0.2	10	4

Is the plant population under balancing selection? If not, which allele will become fixed eventually? (2 points)

Answer 1

SOLUTION - Fixation time is shorter when the allele is dominant than when it is recessive due to occurrence of random . fixation of deleterious allele undee continued mutation pressure → Sarger I change populations with recessive allele are unlikely to quickly as a result, fixation time increases.