Older adults are most likely to develop shingles, which is why the shingles vaccine is recommended for people age 60 and older. Zostavax is currently the only vaccine approved by the Food and Drug Administration (FDA) to prevent shingles.
Polygenic traits are those traits that are controlled by more than one gene. Such traits may even be controlled by genes located on entirely different chromosomes. Human height, eye and hair color are examples of polygenic traits. Skin color is another polygenic trait for humans and a variety of other animals.
Human skin, hair, and eye color are also polygenic traits because they are influenced by more than one allele at different loci. The result is the perception of continuous gradation in the expression of these traits.