Dominant traits are the most common traits in a population.

People frequently assume wrongly that the majority of the population exhibits this quality when they hear the phrase "dominant." The term "dominant" does not necessarily imply "most prevalent," but rather "expressed over the recessive." For instance, the dominant allele of a specific gene governs the behavior of tongue rolling (R).

People with one or two copies of R will roll their tongues. Only those who lack the capacity to tongue roll have two recessive copies of the gene (r). What does this indicate about how prevalent or uncommon tongue rolling is in a population, though?

It is not related to a trait's recessiveness or dominance how frequently it is seen in a population. Instead, it reflects how frequently a person carries the gene that causes a particular feature. For instance, a dominant mutation can be the root cause of polydactyly, which is the occurrence of extra fingers and/or toes.

However, depending on ethnic background, polydactyly only occurs in 0.31-6.18 births per 1,000. Even though the dominant gene mutation that causes polydactyly is exceedingly uncommon, it does exist.