Which trait exhibits typical dominant or recessive inheritance in humans?

One of the classic examples of a trait exhibiting typical dominant or recessive inheritance in humans is attached earlobes versus free-hanging (unattached) earlobes.

• Attached Earlobes (Recessive Trait): This trait is often considered the recessive allele. People with attached earlobes have the skin of their earlobes attached directly to the side of their head without a free-hanging lobe.
• Free-Hanging (Unattached) Earlobes (Dominant Trait): The free-hanging earlobe trait is typically considered the dominant allele. People with this trait have earlobes that hang freely and are not attached directly to the side of their head.

The inheritance pattern follows Mendelian genetics, where the dominant allele (free-hanging earlobes) will mask the expression of the recessive allele (attached earlobes) when present. Therefore, if an individual has at least one copy of the dominant allele (Ff or FF), they will have free-hanging earlobes. Only individuals who are homozygous for the recessive allele (ff) will exhibit the attached earlobe phenotype.