Question

Rebecca went to a genetic counselor. When she had testing done she found that she was a carrier for the disease Tay Sachs. She showed no signs of the disorder; but she could pass the trait on to her offspring. Which of the following would correctly represent Rebecca’s genotype?

NN
Nn
nn
Nt

Answer 1

Rebecca's genotype for carrying Tay-Sachs disease, an autosomal recessive disorder, is represented as Nn.

Step-by-step explanation:

Rebecca found out that she is a carrier for Tay-Sachs disease, which is an autosomal recessive disorder. Since she shows no signs of the disorder but can pass the trait to her offspring, her genotype would be represented as Nn, where 'N' is the normal allele and 'n' is the allele for Tay-Sachs. A person must have two copies of the recessive allele (nn) to express the disease, while carriers like Rebecca have one normal and one recessive allele.

Answer 2

Nn

Step-by-step explanation:

Tay-Sachs disease is an inheritable genetic disorder that results in the destruction of nerve cells in the brain and spinal cord. It's caused by the absence of an enzyme that helps break down fatty substances called gangliosides. Their buildup results in the destruction of nerve cells.

Tay-Sachs is inherited in an autosomal recessive manner. This means that a person needs to have two recessive alleles (nn) in order to inherit it. Rebecca is a carrier of the disease but isn't actually ill. This means that she has one recessive (n) and one dominant (N) allele. Thus, her genotype is Nn.