What is the Punnet square to show all of the possible genotypes of the offspring of a male(no family history of Niemann type A) and woman carrier?

Expert Answers
justaguide eNotes educator| Certified Educator

Niemann Pick disease Type A is a disease that is acquired if both the alleles or copies of the gene that control the production of the enzyme acid sphingomyelinase (ASM) are mutated in a person.

This happens only if both the parents of the child are carriers.

If the offspring's father is not a carrier of the disease and therefore has normal genes and the mother is a carrier and has one mutant allele, the child will not acquire the disease.

The Punnett square to show all the possible genotypes is:

....................Mother (N M)

Father         N N         N M

(N N)          N N         M N

(Bold: genome of offspring)

There is a 2 in 4 chance that the offspring is a carrier of the disease and a 2 in 4 chance that the offspring is healthy and does not carry any mutation of the gene that leads to the disease.