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.
Time signatures always have multiples of two as their bottom numbers. Two, four, eight, 16. While you might not be able to immediately tell what the time signature is of a song, songwriters usually choose the bottom number of the time signature based on what will make it the easiest to count.