These hairs are the mid-phalangeal hairs. This trait is called ad mid-digit hair and is not controlled by a single allele pair. Several studies have shown that these hairs are also controlled by environmental factors as well. The presence of such hair is a dominant trait, and thus, this trait will be passed on to the future generations also. The absence of hairs will be there if only both the recessive alleles are expressed and are environmentally favored also.
