11.   Biologists have long suspected that mutant genes pass the potential for schizophrenia from generation to generation but that they have to be turned on by something in the environment.

12.   A fraction of people of Caucasian ancestry possess one or two copies of this mutant gene.

13.   But first he passed on the mutant gene to his five children.

14.   But when she found out she had one of the mutant genes, the medical community could offer no hard-and-fast answers on what she should do next.

15.   Evidence is emerging that many Jewish women have a mutant gene that greatly increases their risk for ovarian and breast cancer.

16.   For one thing, the mere discovery of a mutant gene tells scientists little about how changes in that gene produce disease.

17.   If the mutant gene is churning out mutant proteins, then each four-ribbon tangle likely has a mutant among its strands.

18.   Larger studies will be needed to determine whether the mutant gene helps explain why AIDS is so common in Africa compared with Europe and the United States.

19.   Non-engineered plants with a mutant gene for herbicide resistance showed nowhere near the level of erosion of family values.

20.   One in five Caucasian Americans carries one copy of the mutant gene.