Whatâs more, they are not regulated by the FDA. This means manufacturers can put in anything they want to, including cheap toxic chemicals with highly harmful effects in the body. Why does this matter if youâre not drinking shampoo? Any substance you rub on your skin or inhale will enter your body just as surely as if you had swallowed it.
Recessive trait. Definition. noun. (genetics) A genetic trait that results from the expression of the two recessive alleles. Supplement. When the dominant allele is lacking or when the two alleles present are both recessive, their expression results in a recessive trait.
Recessive Inheritance. When a trait is recessive, an individual must have two copies of a recessive allele to express the trait. Recessive alleles are denoted by a lowercase letter (a versus A). Only individuals with an aa genotype will express a recessive trait; therefore, offspring must receive one recessive allele from each parent to exhibit a recessive trait. One example of a recessive inherited trait is a smooth chin, as opposed to a dominant cleft chin.