A person with sickle cell trait has ___ mutated copies of the hemoglobin gene, a person with sickle cell disease has ___ mutated copies.

A person with sickle cell trait has one mutated copy of the hemoglobin gene, a person with sickle cell disease has two mutated copies.

Explanation:

Sickle cell disease also known as sickle cell anemia is caused by mutation of the beta chain of hemoglobin, the gene for which lies in 11th number chromosome. If a person possess only one mutated gene, then the disease is not expressed in the person. The person then only possess the trait for sickle cell anemia, that is, there is a chance of sickle cell disease in the offspring, but the sickle cell trait are usually asymptomatic or live like normal individual. While the person possessing two mutated gene is said to be suffering from sickle cell anemia and is found to possess S hemoglobin in the red blood cells which is abnormal hemoglobin without any ability to carry oxygen.