Sarah's mother has Huntington's disease,an illness that results from a dominant gene.Her father,on the other hand,does not have the illness. What is the likelihood that Sarah herself will develop the disease?

Question

Sarah's mother has Huntington's disease,an illness that results from a dominant gene.Her father,on the other hand,does not have the illness. What is the likelihood that Sarah herself will develop the disease?​

Quizplus · Accepted Answer

Since Huntington's disease is caused by a dominant gene, it means that if Sarah's mother has the illness, she must have inherited a copy of the disease-causing gene from her mother. If Sarah's mother has only one copy of the gene, then Sarah has a 50 percent chance of inheriting the same gene and developing the disease, and a 50 percent chance of inheriting a healthy allele from her father and not developing the disease. Therefore, the correct answer is B.

Sarah's Mother Has Huntington's Disease,an Illness That Results from a Dominant