An athletic 21-year old, African-American male in good healthjoined a climb partway up Mt. Rainier in Washington. Despite hisoverall fitness, the rigors of the climb were far greater than heexpected, and he found himself breathing heavily. At an elevationof 6000 feet, he began to feel twinges of pain on the left side ofhis upper abdomen. At 9000 feet, the pain worsened to the pointthat he stopped climbing and descended the mountain. The painbecame very severe during the days after his climb. He went to theemergency room, where tests revealed a disorder in his red bloodcells due to an abnormal form of the protein hemoglobin. Thepatient had a condition called sickle-cell trait. Such individualsare carriers of the gene that causes sickle-cell disease. How doesa gene mutation result in a change in the quaternary structure ofhemoglobin and how does this impact a person's blood when exposedto low oxygen?
