Question

Consider a gene with two alleles that show complete dominance. When two heterozygotes for this gene breed, they have a 25 percent chance of producing a homozygous recessive offspring. The next time these two individuals breed, what are the chances that they will once again have a homozygous recessive progeny?
a. 75 percent
b. 50 percent
c. 25 percent
d. 0 percent

Answer 1

b. 50 percent

Each time the heterozygotes breed, there is a 25 percent chance of producing a homozygous recessive offspring. Therefore, the chances of producing a homozygous recessive progeny the next time they breed is independent of previous events, and remains at 25 percent.