I'm guessing that's why some of the SPY's dividends are unqualified. Page 34 of the same website contains the tax information for the DIA. The DIA paid $2.93 a share in 2008, all of which is qualified.
The mutated gene is passed down through a family, and each generation of children can inherit the gene that causes the disease. Rarely, one of these monogenic diseases can occur spontaneously in a child when his/her parents do not have the disease gene, or there is no history of the disease in the family.
In pedigrees of families with multiple affected generations, autosomal recessive single-gene diseases often show a clear pattern in which the disease skips one or more generations. Phenylketonuria (PKU) is a prominent example of a single-gene disease with an autosomal recessive inheritance pattern.