Research during the 1930s led to the discovery of an important region in human c

Research during the 1930s led to the discovery of an important region in human chromosomes known as the telomere. The enzyme telomerase enables the replacement of the telomere region in a chromosome. Assure Jane Marlow that gene testing or DNA testing has become a widely used tool to identify many disorders and can be a valuable tool for diagnosing conditions early on so that appropriate steps can be taken to prevent further risks of developing diseases. Addresss the following:

• What is the function of telomeres with regard to cell division?
• If a patient has an abnormality in telomerase activity, how might this contribute to cancer?

Duchenne muscular dystrophy (DMD) is an X-linked disease for which prenatal diagnostic testing can be performed.

• Has prenatal genetic testing increased the detection rate of this disease, compared to prior diagnostic methods?
• If so, how? If not, why?
• In case the fetus is diagnosed with DMD and parents decide to terminate the pregnancy, are there chances that the next child will also be a carrier of the disease?

Jane Hill’s husband, Charlie Marlow, has hemophilia A when he marries Hill, who does not have the disorder. Jane’s parents also do not have hemophilia, but her brother Steve Hill does.

• What is the probability that the Marlows’ son will have the disorder?
• What is the probability that their daughter will have hemophilia?
• Are there chances that their daughter will be a carrier of this disorder?