21.   Nor do they know precisely which drugs repair which faulty genes.

22.   Ryuzo Yanagimachi of the University of Hawaii said that even cloned mice that appear to be normal in his laboratory suffer from faulty gene expression.

23.   The disease is caused by a faulty gene.

24.   The ultimate goal is treatments to block or reverse the workings of these flaws, or even knock out the faulty gene and replace it with a perfect one.

25.   Researchers emphasize that they believe infections will add to a mix of known factors causing mental illness rather than replace faulty genes and life experience as a primary cause.