Genes aren't the only factor. Because you inherit one APOE gene from your mother and another from your father, you have two copies of the APOE gene. Having at least one APOE e4 gene increases your risk of developing Alzheimer's disease. If you have two APOE e4 genes, your risk is even higher.
Compound Time Signatures In compound time signatures, the beat occurs on a dotted note and is divisible by three. The most common compound time signatures are 6/8, 9/8 12/8.
The top number of a time signature indicates... how many beats per measure. The bottom number of a time signature indicates... what kind of note (or rest) gets one beat. The top number of a time signature... can be any number, but is usually between 2-12. The bottom number of a time signature... can only 2, 4, 8, or 16.