The gene for Tay-Sachs disease codes for a nonfunctional form of the enzyme hexosaminidase A (or Hex A ) It has been found that a person with only one-third the maximum amount of Hex A can function absolutely normally. Please characterize the heredity of Tay-Sachs disease.
A) codominant
B) recessive
C) dominant
D) multiple allelic

Question

Quizplus · Accepted Answer

Tay-Sachs disease is inherited in a recessive manner, meaning that a person must inherit two copies of the nonfunctional gene (one from each parent) to develop the disease. If a person inherits only one copy of the gene, they are a carrier and do not develop the disease but can pass it on to their offspring. The fact that a person with only one-third the maximum amount of Hex A can function normally suggests that having one functional copy of the gene is enough for normal enzyme activity and function.

The Gene for Tay-Sachs Disease Codes for a Nonfunctional Form