1.   A normal gene produces a normal protein, then something goes wrong and the body starts turning out prions.

2.   These discoveries raise intriguing questions about the relationship between viral genes and the normal genes of the cell.

3.   They found that by introducing a normal gene to substitute the defective one, the mice recovered from the illness.

4.   The normal gene is preserved in tissue culture at the laboratory, tests are due to take place on humans in the Oxford area in the next few months.

5.   And these microchromosomal structures behave as normal genes, bestowing a few trace traits on the Amazon offspring.

6.   Because each cell has a number of the mitochondria, a person may simultaneously have mutated and normal mitochondrial genes.

7.   A normal gene makes a normal protein and a diseased gene presumably makes an abnormal protein.

8.   For cancers that are not inherited, the two-hit hypothesis suggests that alterations must occur in both copies of a normal gene.

9.   For some disorders, the approach has several advantages over normal gene therapy.