Solutions For An Introduction to Genetic Analysis Chapter 18 Problem 40P

In the homozygous condition, the sd gene is lethal in infants. The mutation rate from Sd to sd is 2 x 10^-4. The relative fitness of Sd/Sd homozygotes is 1.0.

Assuming Hardy Weinberg equilibrium:

• p² is Sd/Sd

• 2pq is Sd/sd

• q² is sd/sd

Since 1 out of 100,000 children die, it is the frequency of q². This gives the value of q as 0.003. Then, the value of p is 0.997[1-q].

At equilibrium, since this allele has some effect on Sd/sd fitness, it can be calculated in this way:

The relative fitness of a heterozygous Sd/sd genotype will be lower than 1 for the obtained value of h: