Question

1.    In humans, Tay Sachs disease is a disorder is a recessive disease that causes an absence of enzymes needed to break down fatty substances. However, even if it is a recessive disorder, heterozygous individuals have a “partial manifestation” of Tay Sachs disease, where-in these individuals are able to produce half of the enzymes needed by the body, therefore making them normal individuals. Use the letter H to represent the traits.

a.    What type of inheritance is shown by Tay Sachs? Explain in not more than 5 sentences. (2 pts)

 

 

 

b.    Show a Punnett square solution of a heterozygous mother and a normal, non-carrier father. What is the genotypic and phenotypic ratio of the offsprings? (3 pts)

Answer 1

Autosomal recessive disorder ;

It's caused by the absence of an enzyme that helps break down fatty substances. These fatty substances, called gangliosides, build up to toxic levels in the child's brain and affect the function of the nerve cells.