1.   Crow said the new work strengthens the argument that most organisms reproduce sexually because it lets them get rid of gene flaws more efficiently.

2.   In cloned humans, Jaenisch said the gene expression flaws could affect personality, intelligence and other human attributes.

3.   Researchers probing the genetic mutations that make some people more susceptible than others to cancer have isolated specific gene flaws for leukemia and for breast and kidney cancer.

4.   Their form of SCID was caused by a gene flaw that blocks production of an enzyme called ADA, which is essential to make disease-fighting immune cells.