Question

Early in the 20th century, eugenics proponents thought that if those with genetic diseases were prevented from having children, then the diseases would disappear. They were erroneous in their reasoning, however. Why wouldn't this strategy work for autosomal recessive diseases?

(A) because only females are carriers
(B) because only males are carriers
(C) because the genes would be "protected" in carriers
(D) because 1/4 of all children would be normal

Answer 1

The eugenics proposal to prevent genetic disease transmission wouldn't work for autosomal recessive diseases because carriers can pass on disease-causing genes without showing symptoms, preserving the genes in the population.

Step-by-step explanation:

The strategy of preventing those with genetic diseases from having children would not work for autosomal recessive diseases because the genes causing these diseases can be 'protected' in carriers (option C). Carriers of an autosomal recessive gene have one normal allele and one disease-causing allele and do not show symptoms of the disease. These carriers can pass the disease-causing allele to their offspring without being aware of it. When two carriers have a child, there is a 25% chance that the child will inherit two copies of the recessive allele and express the disease. Even if carriers were to avoid having children, the recessive alleles would maintain themselves within the population because individuals can still carry and pass on the genes without showing any signs of the disease.